diff --git a/system/api_lib.py b/system/api_lib.py
index e1a07757..a32beda3 100644
--- a/system/api_lib.py
+++ b/system/api_lib.py
@@ -5,6 +5,7 @@ import random
 import shutil
 import string
 import time
+import tempfile
 
 from lib import BaseTest
 
@@ -18,11 +19,32 @@ TASK_SUCCEEDED = 2
 TASK_FAILED = 3
 
 
+class AptlyStream:
+    def __init__(self):
+        self.tmp_file = tempfile.NamedTemporaryFile(delete=False)
+        self.read_pos = 0
+
+    def fileno(self):
+        return self.tmp_file.fileno()
+
+    def get_contents(self):
+        self.tmp_file.seek(self.read_pos, 0)
+        return self.tmp_file.read().decode("utf-8")
+
+    def close(self):
+        self.tmp_file.close()
+
+    def clear(self):
+        self.read_pos = self.tmp_file.tell()
+
+
 class APITest(BaseTest):
     """
     BaseTest + testing aptly API
     """
     aptly_server = None
+    aptly_out = None
+    debugOutput = True
     base_url = "127.0.0.1:8765"
     configOverride = {
         "FileSystemPublishEndpoints": {
@@ -40,13 +62,20 @@ class APITest(BaseTest):
         if APITest.aptly_server is None:
             super(APITest, self).prepare()
 
+            APITest.aptly_out = AptlyStream()
+
             configPath = os.path.join(os.environ["HOME"], self.aptlyConfigFile)
-            APITest.aptly_server = self._start_process(f"aptly api serve -no-lock -config={configPath} -listen={self.base_url}",)
+            APITest.aptly_server = self._start_process(f"aptly api serve -no-lock -config={configPath} -listen={self.base_url}", stdout=APITest.aptly_out, stderr=APITest.aptly_out)
             time.sleep(1)
+        else:
+            APITest.aptly_out.clear()
 
         if os.path.exists(os.path.join(os.environ["HOME"], self.aptlyDir, "upload")):
             shutil.rmtree(os.path.join(os.environ["HOME"], self.aptlyDir, "upload"))
 
+    def debug_output(self):
+        return APITest.aptly_out.get_contents()
+
     def run(self):
         pass
 
@@ -79,6 +108,20 @@ class APITest(BaseTest):
 
         return self.get("/api/tasks/" + str(_id))
 
+    def check_task(self, task):
+        self.check_equal(task.status_code, 200)
+        if task.json()['State'] != TASK_SUCCEEDED:
+            resp2 = self.get("/api/tasks/" + str(task.json()['ID']) + "/output")
+            raise Exception(f"task failed: {resp2.text}")
+
+    def check_task_fail(self, task, expected_output=None):
+        self.check_equal(task.status_code, 200)
+        if task.json()['State'] == TASK_SUCCEEDED:
+            raise Exception("task expected to fail")
+        if expected_output:
+            resp = self.get("/api/tasks/" + str(task.json()['ID']) + "/output")
+            self.check_equal(resp.text, expected_output)
+
     def put(self, uri, *args, **kwargs):
         if "json" in kwargs:
             kwargs["data"] = json.dumps(kwargs.pop("json"))
@@ -142,6 +185,8 @@ class APITest(BaseTest):
             cls.aptly_server.terminate()
             cls.aptly_server.wait()
             cls.aptly_server = None
+        if APITest.aptly_out is not None:
+            APITest.aptly_out.close()
 
     def random_name(self):
         return ''.join(random.choice(string.ascii_letters + string.digits) for _ in range(15))
diff --git a/system/lib.py b/system/lib.py
index 66904104..64bb18e9 100644
--- a/system/lib.py
+++ b/system/lib.py
@@ -128,6 +128,7 @@ class BaseTest(object):
     requiresGPG2 = False
     requiresDot = False
     sortOutput = False
+    debugOutput = False
 
     aptlyDir = ".aptly"
     aptlyConfigFile = ".aptly.conf"
@@ -177,6 +178,10 @@ class BaseTest(object):
         try:
             self.run()
             self.check()
+        except Exception as exc:
+            if self.debugOutput:
+                print(f"API log:\n{self.debug_output()}")
+            raise exc
         finally:
             self.teardown()
 
diff --git a/system/run.py b/system/run.py
index bd6de289..71cebe49 100755
--- a/system/run.py
+++ b/system/run.py
@@ -153,10 +153,8 @@ def run(include_long_tests=False, capture_results=False, tests=None, filters=Non
 
         for (test, t, typ, val, tb, testModule) in fails:
             doc = t.__doc__ or ''
-            print("%s:%s %s" % (test, t.__class__.__name__,
-                                testModule.__name__ + ": " + doc.strip()))
-            traceback.print_exception(typ, val, tb)
-            print("=" * 60)
+            print(" - %s:%s %s" % (test, t.__class__.__name__,
+                                   testModule.__name__ + ": " + doc.strip()))
 
         sys.exit(1)
 
diff --git a/system/t12_api/gpg.py b/system/t12_api/gpg.py
index 8fb9a380..e05e165a 100644
--- a/system/t12_api/gpg.py
+++ b/system/t12_api/gpg.py
@@ -7,11 +7,16 @@ from api_lib import APITest
 
 
 def check_gpgkey_exists(gpg_key, keyring):
-    subprocess.check_call([
+    p = subprocess.Popen([
         "gpg", "--no-default-keyring",
         "--keyring", keyring,
-        "--fingerprint", gpg_key,
-    ])
+        "--fingerprint", gpg_key],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+    )
+    p.communicate()
+    if p.returncode != 0:
+        raise Exception("gpg key does not exists")
 
 
 class GPGAPITestAddKey(APITest):
diff --git a/system/t12_api/mirrors.py b/system/t12_api/mirrors.py
index 88e1915b..6352b2ca 100644
--- a/system/t12_api/mirrors.py
+++ b/system/t12_api/mirrors.py
@@ -1,4 +1,4 @@
-from api_lib import TASK_SUCCEEDED, APITest
+from api_lib import APITest
 
 
 class MirrorsAPITestCreateShow(APITest):
@@ -58,11 +58,8 @@ class MirrorsAPITestCreateUpdate(APITest):
 
         mirror_desc["Name"] = self.random_name()
         resp = self.put_task("/api/mirrors/" + mirror_name, json=mirror_desc)
-        self.check_equal(resp.status_code, 200)
+        self.check_task(resp)
         _id = resp.json()['ID']
-        if resp.json()["State"] != TASK_SUCCEEDED:
-            resp = self.get("/api/tasks/" + str(_id) + "/output")
-            raise Exception("task failed: " + str(resp.json()))
 
         resp = self.get("/api/tasks/" + str(_id) + "/detail")
         self.check_equal(resp.status_code, 200)
@@ -95,7 +92,7 @@ class MirrorsAPITestCreateDelete(APITest):
         self.check_equal(resp.status_code, 201)
 
         resp = self.delete_task("/api/mirrors/" + mirror_name)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(resp)
 
 
 class MirrorsAPITestCreateList(APITest):
@@ -154,8 +151,4 @@ class MirrorsAPITestSkipArchitectureCheck(APITest):
         mirror_desc = {'Name': mirror_name,
                        'IgnoreSignatures': True}
         resp = self.put_task("/api/mirrors/" + mirror_name, json=mirror_desc)
-        self.check_equal(resp.status_code, 200)
-        _id = resp.json()['ID']
-        if resp.json()["State"] != TASK_SUCCEEDED:
-            resp = self.get("/api/tasks/" + str(_id) + "/output")
-            raise Exception("task failed: " + str(resp.json()))
+        self.check_task(resp)
diff --git a/system/t12_api/packages.py b/system/t12_api/packages.py
index 90e8844e..86cf6ea1 100644
--- a/system/t12_api/packages.py
+++ b/system/t12_api/packages.py
@@ -2,7 +2,7 @@ import urllib.error
 import urllib.parse
 import urllib.request
 
-from api_lib import TASK_SUCCEEDED, APITest
+from api_lib import APITest
 
 
 class PackagesAPITestShow(APITest):
@@ -19,7 +19,7 @@ class PackagesAPITestShow(APITest):
                          "pyspi_0.6.1-1.3.dsc", "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz").status_code, 200)
 
         resp = self.post_task("/api/repos/" + repo_name + "/file/" + d)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(resp)
 
         # get information about package
         pyspi_json = {
diff --git a/system/t12_api/publish.py b/system/t12_api/publish.py
index 94765ec3..4ecffbc1 100644
--- a/system/t12_api/publish.py
+++ b/system/t12_api/publish.py
@@ -27,11 +27,12 @@ class PublishAPITestRepo(APITest):
                                      "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz",
                                      "pyspi-0.6.1-1.3.stripped.dsc").status_code, 200)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
         # publishing under prefix, default distribution
         prefix = self.random_name()
-        resp = self.post_task(
+        task = self.post_task(
             "/api/publish/" + prefix,
             json={
                  "SourceKind": "local",
@@ -39,6 +40,7 @@ class PublishAPITestRepo(APITest):
                  "Signing": DefaultSigningOptions,
             }
         )
+        self.check_task(task)
         repo_expected = {
             'AcquireByHash': False,
             'Architectures': ['i386', 'source'],
@@ -56,8 +58,6 @@ class PublishAPITestRepo(APITest):
             'Storage': '',
             'Suite': ''}
 
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
-
         all_repos = self.get("/api/publish")
         self.check_equal(all_repos.status_code, 200)
         self.check_in(repo_expected, all_repos.json())
@@ -74,7 +74,7 @@ class PublishAPITestRepo(APITest):
 
         # publishing under root, custom distribution, architectures
         distribution = self.random_name()
-        resp = self.post_task(
+        task = self.post_task(
             "/api/publish/:.",
             json={
                  "SourceKind": "local",
@@ -84,7 +84,7 @@ class PublishAPITestRepo(APITest):
                  "Architectures": ["i386", "amd64"],
             }
         )
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
         repo2_expected = {
             'AcquireByHash': False,
             'Architectures': ['amd64', 'i386'],
@@ -138,12 +138,14 @@ class PublishSnapshotAPITest(APITest):
         self.check_equal(self.upload("/api/files/" + d,
                                      "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot_name}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot_name})
+        self.check_task(task)
 
         prefix = self.random_name()
-        resp = self.post_task(
+        task = self.post_task(
             "/api/publish/" + prefix,
             json={
                 "AcquireByHash": True,
@@ -157,9 +159,9 @@ class PublishSnapshotAPITest(APITest):
                 "Label": "fun",
             }
         )
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
 
-        _id = resp.json()['ID']
+        _id = task.json()['ID']
         resp = self.get("/api/tasks/" + str(_id) + "/detail")
         self.check_equal(resp.json()['RemainingNumberOfPackages'], 0)
         self.check_equal(resp.json()['TotalNumberOfPackages'], 1)
@@ -213,10 +215,11 @@ class PublishUpdateAPITestRepo(APITest):
                         "pyspi_0.6.1-1.3.dsc",
                         "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz",
                         "pyspi-0.6.1-1.3.stripped.dsc").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
         prefix = self.random_name()
-        resp = self.post_task(
+        task = self.post_task(
             "/api/publish/" + prefix,
             json={
                 "Architectures": ["i386", "source"],
@@ -225,8 +228,7 @@ class PublishUpdateAPITestRepo(APITest):
                 "Signing": DefaultSigningOptions,
             }
         )
-
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
 
         self.check_not_exists(
             "public/" + prefix + "/pool/main/b/boost-defaults/libboost-program-options-dev_1.49.0.1_i386.deb")
@@ -236,20 +238,22 @@ class PublishUpdateAPITestRepo(APITest):
         d = self.random_name()
         self.check_equal(self.upload("/api/files/" + d,
                          "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
-        self.check_equal(self.delete_task("/api/repos/" + repo_name + "/packages/",
-                         json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']}).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/repos/" + repo_name + "/packages/",
+                                json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']})
+        self.check_task(task)
 
         # Update and switch AcquireByHash on.
-        resp = self.put_task(
+        task = self.put_task(
             "/api/publish/" + prefix + "/wheezy",
             json={
                 "AcquireByHash": True,
                 "Signing": DefaultSigningOptions,
             }
         )
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
         repo_expected = {
             'AcquireByHash': True,
             'Architectures': ['i386', 'source'],
@@ -279,7 +283,8 @@ class PublishUpdateAPITestRepo(APITest):
         self.check_not_exists(
             "public/" + prefix + "/pool/main/p/pyspi/pyspi-0.6.1-1.3.stripped.dsc")
 
-        self.check_equal(self.delete_task("/api/publish/" + prefix + "/wheezy").json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/publish/" + prefix + "/wheezy")
+        self.check_task(task)
         self.check_not_exists("public/" + prefix + "dists/")
 
 
@@ -300,10 +305,11 @@ class PublishConcurrentUpdateAPITestRepo(APITest):
                         "pyspi_0.6.1-1.3.dsc",
                         "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz",
                         "pyspi-0.6.1-1.3.stripped.dsc").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
         prefix = self.random_name()
-        resp = self.post_task(
+        task = self.post_task(
             "/api/publish/" + prefix,
             json={
                 "Architectures": ["i386", "source"],
@@ -312,8 +318,7 @@ class PublishConcurrentUpdateAPITestRepo(APITest):
                 "Signing": DefaultSigningOptions,
             }
         )
-
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
 
         self.check_not_exists(
             "public/" + prefix + "/pool/main/b/boost-defaults/libboost-program-options-dev_1.49.0.1_i386.deb")
@@ -323,10 +328,12 @@ class PublishConcurrentUpdateAPITestRepo(APITest):
         d = self.random_name()
         self.check_equal(self.upload("/api/files/" + d,
                          "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
-        self.check_equal(self.delete_task("/api/repos/" + repo_name + "/packages/",
-                         json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']}).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/repos/" + repo_name + "/packages/",
+                                json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']})
+        self.check_task(task)
 
         def _do_update(result, index):
             resp = self.put_task(
@@ -379,7 +386,8 @@ class PublishConcurrentUpdateAPITestRepo(APITest):
         self.check_not_exists(
             "public/" + prefix + "/pool/main/p/pyspi/pyspi-0.6.1-1.3.stripped.dsc")
 
-        self.check_equal(self.delete_task("/api/publish/" + prefix + "/wheezy").json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/publish/" + prefix + "/wheezy")
+        self.check_task(task)
         self.check_not_exists("public/" + prefix + "dists/")
 
 
@@ -400,18 +408,18 @@ class PublishUpdateSkipCleanupAPITestRepo(APITest):
                         "pyspi_0.6.1-1.3.dsc",
                         "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz",
                         "pyspi-0.6.1-1.3.stripped.dsc").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
         prefix = self.random_name()
-        resp = self.post_task("/api/publish/" + prefix,
+        task = self.post_task("/api/publish/" + prefix,
                               json={
                                   "Architectures": ["i386", "source"],
                                   "SourceKind": "local",
                                   "Sources": [{"Name": repo_name}],
                                   "Signing": DefaultSigningOptions,
                               })
-
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
 
         self.check_not_exists(
             "public/" + prefix + "/pool/main/b/boost-defaults/libboost-program-options-dev_1.49.0.1_i386.deb")
@@ -420,7 +428,7 @@ class PublishUpdateSkipCleanupAPITestRepo(APITest):
 
         # Publish two repos, so that deleting one while skipping cleanup will
         # not delete the whole prefix.
-        resp = self.post_task("/api/publish/" + prefix,
+        task = self.post_task("/api/publish/" + prefix,
                               json={
                                   "Architectures": ["i386", "source"],
                                   "Distribution": "otherdist",
@@ -428,23 +436,24 @@ class PublishUpdateSkipCleanupAPITestRepo(APITest):
                                   "Sources": [{"Name": repo_name}],
                                   "Signing": DefaultSigningOptions,
                               })
-
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
 
         d = self.random_name()
         self.check_equal(self.upload("/api/files/" + d,
                          "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
-        self.check_equal(self.delete_task("/api/repos/" + repo_name + "/packages/",
-                         json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']}).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/repos/" + repo_name + "/packages/",
+                                json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']})
+        self.check_task(task)
 
-        resp = self.put_task("/api/publish/" + prefix + "/wheezy",
+        task = self.put_task("/api/publish/" + prefix + "/wheezy",
                              json={
                                  "Signing": DefaultSigningOptions,
                                  "SkipCleanup": True,
                              })
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
         repo_expected = {
             'AcquireByHash': False,
             'Architectures': ['i386', 'source'],
@@ -471,7 +480,8 @@ class PublishUpdateSkipCleanupAPITestRepo(APITest):
         self.check_exists("public/" + prefix +
                           "/pool/main/p/pyspi/pyspi-0.6.1-1.3.stripped.dsc")
 
-        self.check_equal(self.delete_task("/api/publish/" + prefix + "/wheezy", params={"SkipCleanup": "1"}).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/publish/" + prefix + "/wheezy", params={"SkipCleanup": "1"})
+        self.check_task(task)
         self.check_exists("public/" + prefix + "/pool/main/b/boost-defaults/libboost-program-options-dev_1.49.0.1_i386.deb")
         self.check_exists("public/" + prefix + "/pool/main/p/pyspi/pyspi-0.6.1-1.3.stripped.dsc")
 
@@ -493,13 +503,15 @@ class PublishSwitchAPITestRepo(APITest):
                         "pyspi_0.6.1-1.3.dsc",
                         "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz",
                         "pyspi-0.6.1-1.3.stripped.dsc").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
         snapshot1_name = self.random_name()
-        self.check_equal(self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot1_name}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot1_name})
+        self.check_task(task)
 
         prefix = self.random_name()
-        resp = self.post_task(
+        task = self.post_task(
             "/api/publish/" + prefix,
             json={
                 "Architectures": ["i386", "source"],
@@ -507,8 +519,8 @@ class PublishSwitchAPITestRepo(APITest):
                 "Sources": [{"Name": snapshot1_name}],
                 "Signing": DefaultSigningOptions,
             })
+        self.check_task(task)
 
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
         repo_expected = {
             'AcquireByHash': False,
             'Architectures': ['i386', 'source'],
@@ -537,22 +549,25 @@ class PublishSwitchAPITestRepo(APITest):
         d = self.random_name()
         self.check_equal(self.upload("/api/files/" + d,
                          "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
-        self.check_equal(self.delete_task("/api/repos/" + repo_name + "/packages/",
-                         json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']}).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/repos/" + repo_name + "/packages/",
+                                json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']})
+        self.check_task(task)
 
         snapshot2_name = self.random_name()
-        self.check_equal(self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot2_name}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot2_name})
+        self.check_task(task)
 
-        resp = self.put_task(
+        task = self.put_task(
             "/api/publish/" + prefix + "/wheezy",
             json={
                 "Snapshots": [{"Component": "main", "Name": snapshot2_name}],
                 "Signing": DefaultSigningOptions,
                 "SkipContents": True,
             })
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
         repo_expected = {
             'AcquireByHash': False,
             'Architectures': ['i386', 'source'],
@@ -579,7 +594,8 @@ class PublishSwitchAPITestRepo(APITest):
         self.check_not_exists(
             "public/" + prefix + "/pool/main/p/pyspi/pyspi-0.6.1-1.3.stripped.dsc")
 
-        self.check_equal(self.delete_task("/api/publish/" + prefix + "/wheezy").json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/publish/" + prefix + "/wheezy")
+        self.check_task(task)
         self.check_not_exists("public/" + prefix + "dists/")
 
 
@@ -600,13 +616,15 @@ class PublishSwitchAPISkipCleanupTestRepo(APITest):
                         "pyspi_0.6.1-1.3.dsc",
                         "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz",
                         "pyspi-0.6.1-1.3.stripped.dsc").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
         snapshot1_name = self.random_name()
-        self.check_equal(self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot1_name}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot1_name})
+        self.check_task(task)
 
         prefix = self.random_name()
-        resp = self.post_task("/api/publish/" + prefix,
+        task = self.post_task("/api/publish/" + prefix,
                               json={
                                   "Architectures": ["i386", "source"],
                                   "SourceKind": "snapshot",
@@ -614,7 +632,7 @@ class PublishSwitchAPISkipCleanupTestRepo(APITest):
                                   "Signing": DefaultSigningOptions,
                               })
 
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
         repo_expected = {
             'AcquireByHash': False,
             'Architectures': ['i386', 'source'],
@@ -642,7 +660,7 @@ class PublishSwitchAPISkipCleanupTestRepo(APITest):
 
         # Publish two snapshots, so that deleting one while skipping cleanup will
         # not delete the whole prefix.
-        resp = self.post_task("/api/publish/" + prefix,
+        task = self.post_task("/api/publish/" + prefix,
                               json={
                                   "Architectures": ["i386", "source"],
                                   "Distribution": "otherdist",
@@ -651,7 +669,7 @@ class PublishSwitchAPISkipCleanupTestRepo(APITest):
                                   "Signing": DefaultSigningOptions,
                               })
 
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
         repo_expected = {
             'AcquireByHash': False,
             'Architectures': ['i386', 'source'],
@@ -675,22 +693,25 @@ class PublishSwitchAPISkipCleanupTestRepo(APITest):
         d = self.random_name()
         self.check_equal(self.upload("/api/files/" + d,
                          "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
-        self.check_equal(self.delete_task("/api/repos/" + repo_name + "/packages/",
-                         json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']}).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/repos/" + repo_name + "/packages/",
+                                json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']})
+        self.check_task(task)
 
         snapshot2_name = self.random_name()
-        self.check_equal(self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot2_name}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot2_name})
+        self.check_task(task)
 
-        resp = self.put_task("/api/publish/" + prefix + "/wheezy",
+        task = self.put_task("/api/publish/" + prefix + "/wheezy",
                              json={
                                  "Snapshots": [{"Component": "main", "Name": snapshot2_name}],
                                  "Signing": DefaultSigningOptions,
                                  "SkipCleanup": True,
                                  "SkipContents": True,
                              })
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
         repo_expected = {
             'AcquireByHash': False,
             'Architectures': ['i386', 'source'],
@@ -715,7 +736,8 @@ class PublishSwitchAPISkipCleanupTestRepo(APITest):
         self.check_exists("public/" + prefix + "/pool/main/b/boost-defaults/libboost-program-options-dev_1.49.0.1_i386.deb")
         self.check_exists("public/" + prefix + "/pool/main/p/pyspi/pyspi-0.6.1-1.3.stripped.dsc")
 
-        self.check_equal(self.delete_task("/api/publish/" + prefix + "/wheezy", params={"SkipCleanup": "1"}).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/publish/" + prefix + "/wheezy", params={"SkipCleanup": "1"})
+        self.check_task(task)
         self.check_exists("public/" + prefix + "/pool/main/b/boost-defaults/libboost-program-options-dev_1.49.0.1_i386.deb")
         self.check_exists("public/" + prefix + "/pool/main/p/pyspi/pyspi-0.6.1-1.3.stripped.dsc")
 
diff --git a/system/t12_api/repos.py b/system/t12_api/repos.py
index bc0a43cc..b958e109 100644
--- a/system/t12_api/repos.py
+++ b/system/t12_api/repos.py
@@ -1,4 +1,4 @@
-from api_lib import TASK_FAILED, TASK_SUCCEEDED, APITest
+from api_lib import APITest
 
 from .publish import DefaultSigningOptions
 
@@ -41,7 +41,8 @@ class ReposAPITestCreateIndexDelete(APITest):
         names = [repo["Name"] for repo in repos]
         assert repo_name in names
 
-        self.check_equal(self.delete_task("/api/repos/" + repo_name).json()['State'], TASK_SUCCEEDED)
+        resp = self.delete_task("/api/repos/" + repo_name)
+        self.check_task(resp)
         self.check_equal(self.delete("/api/repos/" + repo_name).status_code, 404)
 
         self.check_equal(self.get("/api/repos/" + repo_name).status_code, 404)
@@ -61,25 +62,32 @@ class ReposAPITestCreateIndexDelete(APITest):
                          "pyspi_0.6.1-1.3.dsc", "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz").status_code, 200)
 
         resp = self.post_task("/api/repos/" + repo_name + "/file/" + d)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(resp)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/snapshots", json={"Name": repo_name}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/snapshots", json={"Name": repo_name})
+        self.check_task(task)
 
-        self.check_equal(self.post_task("/api/publish",
-                         json={
-                             "SourceKind": "local",
-                             "Sources": [{"Name": repo_name}],
-                             "Signing": DefaultSigningOptions,
-                         }).json()['State'], TASK_SUCCEEDED)
+        resp = self.post_task("/api/publish",
+                              json={
+                                  "SourceKind": "local",
+                                  "Sources": [{"Name": repo_name}],
+                                  "Signing": DefaultSigningOptions,
+                              })
+        self.check_task(resp)
 
         # repo is not deletable while it is published
-        self.check_equal(self.delete_task("/api/repos/" + repo_name).json()['State'], TASK_FAILED)
-        self.check_equal(self.delete_task("/api/repos/" + repo_name, params={"force": "1"}).json()['State'], TASK_FAILED)
+        task = self.delete_task("/api/repos/" + repo_name)
+        self.check_task_fail(task)
+        task = self.delete_task("/api/repos/" + repo_name, params={"force": "1"})
+        self.check_task_fail(task)
 
         # drop published
-        self.check_equal(self.delete_task("/api/publish//" + distribution).json()['State'], TASK_SUCCEEDED)
-        self.check_equal(self.delete_task("/api/repos/" + repo_name).json()['State'], TASK_FAILED)
-        self.check_equal(self.delete_task("/api/repos/" + repo_name, params={"force": "1"}).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/publish//" + distribution)
+        self.check_task(task)
+        task = self.delete_task("/api/repos/" + repo_name)
+        self.check_task_fail(task)
+        task = self.delete_task("/api/repos/" + repo_name, params={"force": "1"})
+        self.check_task(task)
         self.check_equal(self.get("/api/repos/" + repo_name).status_code, 404)
 
 
@@ -97,7 +105,7 @@ class ReposAPITestAdd(APITest):
                          "pyspi_0.6.1-1.3.dsc", "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz").status_code, 200)
 
         resp = self.post_task("/api/repos/" + repo_name + "/file/" + d)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(resp)
 
         resp = self.get("/api/tasks/" + str(resp.json()['ID']) + "/output")
         self.check_equal(resp.status_code, 200)
@@ -125,7 +133,8 @@ class ReposAPITestAddNotFullRemove(APITest):
         self.check_equal(self.upload("/api/files/" + d,
                          "pyspi_0.6.1-1.3.dsc", "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz", "aptly.pub").status_code, 200)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
         self.check_equal(self.get("/api/repos/" + repo_name + "/packages").json(), ['Psource pyspi 0.6.1-1.3 3a8b37cbd9a3559e'])
 
         self.check_exists("upload/" + d + "/aptly.pub")
@@ -145,7 +154,8 @@ class ReposAPITestAddNoRemove(APITest):
         self.check_equal(self.upload("/api/files/" + d,
                          "pyspi_0.6.1-1.3.dsc", "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz").status_code, 200)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d, params={"noRemove": 1}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d, params={"noRemove": 1})
+        self.check_task(task)
         self.check_equal(self.get("/api/repos/" + repo_name + "/packages").json(), ['Psource pyspi 0.6.1-1.3 3a8b37cbd9a3559e'])
 
         self.check_exists("upload/" + d + "/pyspi_0.6.1-1.3.dsc")
@@ -165,7 +175,7 @@ class ReposAPITestAddFile(APITest):
                          "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
 
         resp = self.post_task("/api/repos/" + repo_name + "/file/" + d + "/libboost-program-options-dev_1.49.0.1_i386.deb")
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(resp)
 
         resp = self.get("/api/tasks/" + str(resp.json()['ID']) + "/output")
         self.check_equal(resp.status_code, 200)
@@ -197,7 +207,7 @@ class ReposAPITestInclude(APITest):
         self.check_equal(resp.status_code, 200)
 
         resp = self.post_task("/api/repos/" + repo_name + "/include/" + d, params={"ignoreSignature": 1})
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(resp)
 
         resp = self.get("/api/tasks/" + str(resp.json()['ID']) + "/output")
         self.check_equal(resp.status_code, 200)
@@ -225,7 +235,8 @@ class ReposAPITestShowQuery(APITest):
                         "libboost-program-options-dev_1.49.0.1_i386.deb", "pyspi_0.6.1-1.3.dsc",
                         "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz",
                         "pyspi-0.6.1-1.3.stripped.dsc").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
         self.check_equal(sorted(self.get("/api/repos/" + repo_name + "/packages", params={"q": "pyspi"}).json()),
                          ['Psource pyspi 0.6.1-1.3 3a8b37cbd9a3559e', 'Psource pyspi 0.6.1-1.4 f8f1daa806004e89'])
@@ -258,13 +269,15 @@ class ReposAPITestAddMultiple(APITest):
                         "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz",
                         "pyspi-0.6.1-1.3.stripped.dsc").status_code, 200)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d + "/pyspi_0.6.1-1.3.dsc",
-                                        params={"noRemove": 1}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d + "/pyspi_0.6.1-1.3.dsc",
+                              params={"noRemove": 1})
+        self.check_task(task)
 
         self.check_equal(sorted(self.get("/api/repos/" + repo_name + "/packages").json()),
                          ['Psource pyspi 0.6.1-1.3 3a8b37cbd9a3559e'])
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d + "/pyspi-0.6.1-1.3.stripped.dsc").json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d + "/pyspi-0.6.1-1.3.stripped.dsc")
+        self.check_task(task)
 
         self.check_equal(sorted(self.get("/api/repos/" + repo_name + "/packages").json()),
                          ['Psource pyspi 0.6.1-1.3 3a8b37cbd9a3559e', 'Psource pyspi 0.6.1-1.4 f8f1daa806004e89'])
@@ -286,34 +299,39 @@ class ReposAPITestPackagesAddDelete(APITest):
                         "pyspi_0.6.1-1.3.diff.gz", "pyspi_0.6.1.orig.tar.gz",
                         "pyspi-0.6.1-1.3.stripped.dsc").status_code, 200)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
         self.check_equal(sorted(self.get("/api/repos/" + repo_name + "/packages").json()),
                          ['Pi386 libboost-program-options-dev 1.49.0.1 918d2f433384e378',
                           'Psource pyspi 0.6.1-1.3 3a8b37cbd9a3559e',
                           'Psource pyspi 0.6.1-1.4 f8f1daa806004e89'])
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/packages/",
-                         json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/packages/",
+                              json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']})
+        self.check_task(task)
 
         self.check_equal(sorted(self.get("/api/repos/" + repo_name + "/packages").json()),
                          ['Pi386 libboost-program-options-dev 1.49.0.1 918d2f433384e378',
                           'Psource pyspi 0.6.1-1.3 3a8b37cbd9a3559e',
                           'Psource pyspi 0.6.1-1.4 f8f1daa806004e89'])
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/packages/",
-                         json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89',
-                                               'Psource no-such-package 0.6.1-1.4 f8f1daa806004e89']}).json()['State'], TASK_FAILED)
+        task = self.post_task("/api/repos/" + repo_name + "/packages/",
+                              json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89',
+                                                    'Psource no-such-package 0.6.1-1.4 f8f1daa806004e89']})
+        self.check_task_fail(task)
 
-        self.check_equal(self.delete_task("/api/repos/" + repo_name + "/packages/",
-                         json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']}).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/repos/" + repo_name + "/packages/",
+                                json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']})
+        self.check_task(task)
 
         self.check_equal(sorted(self.get("/api/repos/" + repo_name + "/packages").json()),
                          ['Pi386 libboost-program-options-dev 1.49.0.1 918d2f433384e378',
                           'Psource pyspi 0.6.1-1.3 3a8b37cbd9a3559e'])
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/packages/",
-                         json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/packages/",
+                              json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89']})
+        self.check_task(task)
 
         self.check_equal(sorted(self.get("/api/repos/" + repo_name + "/packages").json()),
                          ['Pi386 libboost-program-options-dev 1.49.0.1 918d2f433384e378',
@@ -324,9 +342,10 @@ class ReposAPITestPackagesAddDelete(APITest):
 
         self.check_equal(self.post("/api/repos", json={"Name": repo_name2, "Comment": "fun repo"}).status_code, 201)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name2 + "/packages/",
-                         json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89',
-                                               'Pi386 libboost-program-options-dev 1.49.0.1 918d2f433384e378']}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name2 + "/packages/",
+                              json={"PackageRefs": ['Psource pyspi 0.6.1-1.4 f8f1daa806004e89',
+                                                    'Pi386 libboost-program-options-dev 1.49.0.1 918d2f433384e378']})
+        self.check_task(task)
 
         self.check_equal(sorted(self.get("/api/repos/" + repo_name2 + "/packages").json()),
                          ['Pi386 libboost-program-options-dev 1.49.0.1 918d2f433384e378',
@@ -349,7 +368,7 @@ class ReposAPITestShowMaxVersion(APITest):
                                      ).status_code, 200)
 
         resp = self.post_task("/api/repos/" + repo_name + "/file/" + d)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(resp)
 
         resp = self.get("/api/tasks/" + str(resp.json()['ID']) + "/output")
         self.check_equal(resp.status_code, 200)
@@ -377,7 +396,7 @@ class ReposAPITestCopyPackage(APITest):
         d = self.random_name()
         self.check_equal(self.upload(f"/api/files/{d}", f"{pkg_name}.deb").status_code, 200)
         resp = self.post_task(f"/api/repos/{repo1_name}/file/{d}")
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(resp)
 
         # Creating target repo
         repo2_name = self.random_name()
@@ -385,8 +404,11 @@ class ReposAPITestCopyPackage(APITest):
 
         # Copy the package
         resp = self.post_task(f"/api/repos/{repo2_name}/copy/{repo1_name}/{pkg_name}")
-        self.check_equal(resp.status_code, 200)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(resp)
+
+        # Test non-existing package
+        resp = self.post_task(f"/api/repos/{repo2_name}/copy/{repo1_name}/la<la>la")
+        self.check_task_fail(resp)
 
         self.check_equal(self.get(f"/api/repos/{repo2_name}/packages").json(),
                          ['Pi386 libboost-program-options-dev 1.49.0.1 918d2f433384e378'])
diff --git a/system/t12_api/snapshots.py b/system/t12_api/snapshots.py
index 0d12066a..4276c071 100644
--- a/system/t12_api/snapshots.py
+++ b/system/t12_api/snapshots.py
@@ -1,4 +1,4 @@
-from api_lib import TASK_FAILED, TASK_SUCCEEDED, APITest
+from api_lib import TASK_FAILED, APITest
 
 from .publish import DefaultSigningOptions
 
@@ -13,8 +13,8 @@ class SnapshotsAPITestCreateShowEmpty(APITest):
                          'Name': snapshot_name}
 
         # create empty snapshot
-        resp = self.post_task("/api/snapshots", json=snapshot_desc)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/snapshots", json=snapshot_desc)
+        self.check_task(task)
 
         self.check_subset(snapshot_desc, self.get("/api/snapshots/" + snapshot_name).json())
         self.check_equal(self.get("/api/snapshots/" + snapshot_name).status_code, 200)
@@ -47,8 +47,8 @@ class SnapshotsAPITestCreateFromRefs(APITest):
 
         # create empty snapshot
         empty_snapshot_name = self.random_name()
-        resp = self.post_task("/api/snapshots", json={"Name": empty_snapshot_name})
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/snapshots", json={"Name": empty_snapshot_name})
+        self.check_task(task)
         self.check_equal(
             self.get("/api/snapshots/" + empty_snapshot_name).json()['Description'], "Created as empty"
         )
@@ -59,14 +59,15 @@ class SnapshotsAPITestCreateFromRefs(APITest):
         d = self.random_name()
         self.check_equal(self.upload("/api/files/" + d,
                          "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
         # create snapshot with empty snapshot as source and package
         snapshot = snapshot_desc.copy()
         snapshot['PackageRefs'] = ["Pi386 libboost-program-options-dev 1.49.0.1 918d2f433384e378"]
         snapshot['SourceSnapshots'] = [empty_snapshot_name]
-        resp = self.post_task("/api/snapshots", json=snapshot)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/snapshots", json=snapshot)
+        self.check_task(task)
         snapshot.pop('SourceSnapshots')
         snapshot.pop('PackageRefs')
         resp = self.get("/api/snapshots/" + snapshot_name)
@@ -100,8 +101,8 @@ class SnapshotsAPITestCreateFromRepo(APITest):
         snapshot_name = self.random_name()
         self.check_equal(self.post("/api/repos", json={"Name": repo_name}).status_code, 201)
 
-        resp = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot_name})
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot_name})
+        self.check_task(task)
         self.check_equal([],
                          self.get("/api/snapshots/" + snapshot_name + "/packages", params={"format": "details"}).json())
 
@@ -110,10 +111,11 @@ class SnapshotsAPITestCreateFromRepo(APITest):
         self.check_equal(self.upload("/api/files/" + d,
                          "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
-        resp = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot_name})
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot_name})
+        self.check_task(task)
         self.check_equal(self.get("/api/snapshots/" + snapshot_name).status_code, 200)
 
         self.check_subset({'Architecture': 'i386',
@@ -143,13 +145,13 @@ class SnapshotsAPITestCreateUpdate(APITest):
         snapshot_desc = {'Description': 'fun snapshot',
                          'Name': snapshot_name}
 
-        resp = self.post_task("/api/snapshots", json=snapshot_desc)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/snapshots", json=snapshot_desc)
+        self.check_task(task)
 
         new_snapshot_name = self.random_name()
-        resp = self.put_task("/api/snapshots/" + snapshot_name, json={'Name': new_snapshot_name,
+        task = self.put_task("/api/snapshots/" + snapshot_name, json={'Name': new_snapshot_name,
                                                                       'Description': 'New description'})
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
 
         resp = self.get("/api/snapshots/" + new_snapshot_name)
         self.check_equal(resp.status_code, 200)
@@ -176,16 +178,18 @@ class SnapshotsAPITestCreateDelete(APITest):
                          'Name': snapshot_name}
 
         # deleting unreferenced snapshot
-        resp = self.post_task("/api/snapshots", json=snapshot_desc)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/snapshots", json=snapshot_desc)
+        self.check_task(task)
 
-        self.check_equal(self.delete_task("/api/snapshots/" + snapshot_name).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/snapshots/" + snapshot_name)
+        self.check_task(task)
 
         self.check_equal(self.get("/api/snapshots/" + snapshot_name).status_code, 404)
 
         # deleting referenced snapshot
         snap1, snap2 = self.random_name(), self.random_name()
-        self.check_equal(self.post_task("/api/snapshots", json={"Name": snap1}).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/snapshots", json={"Name": snap1})
+        self.check_task(task)
         self.check_equal(
             self.post_task(
                 "/api/snapshots", json={"Name": snap2, "SourceSnapshots": [snap1]}
@@ -194,11 +198,12 @@ class SnapshotsAPITestCreateDelete(APITest):
 
         self.check_equal(self.delete_task("/api/snapshots/" + snap1).json()['State'], TASK_FAILED)
         self.check_equal(self.get("/api/snapshots/" + snap1).status_code, 200)
-        self.check_equal(self.delete_task("/api/snapshots/" + snap1, params={"force": "1"}).json()['State'], TASK_SUCCEEDED)
+        task = self.delete_task("/api/snapshots/" + snap1, params={"force": "1"})
+        self.check_task(task)
         self.check_equal(self.get("/api/snapshots/" + snap1).status_code, 404)
 
         # deleting published snapshot
-        resp = self.post_task(
+        task = self.post_task(
             "/api/publish",
             json={
                  "SourceKind": "snapshot",
@@ -208,7 +213,7 @@ class SnapshotsAPITestCreateDelete(APITest):
                  "Signing": DefaultSigningOptions,
             }
         )
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        self.check_task(task)
 
         self.check_equal(self.delete_task("/api/snapshots/" + snap2).json()['State'], TASK_FAILED)
         self.check_equal(self.delete_task("/api/snapshots/" + snap2, params={"force": "1"}).json()['State'], TASK_FAILED)
@@ -228,10 +233,11 @@ class SnapshotsAPITestSearch(APITest):
         self.check_equal(self.upload("/api/files/" + d,
                          "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
 
-        self.check_equal(self.post_task("/api/repos/" + repo_name + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + "/file/" + d)
+        self.check_task(task)
 
-        resp = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot_name})
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repo_name + '/snapshots', json={'Name': snapshot_name})
+        self.check_task(task)
 
         resp = self.get("/api/snapshots/" + snapshot_name + "/packages",
                         params={"q": "libboost-program-options-dev", "format": "details"})
@@ -262,13 +268,14 @@ class SnapshotsAPITestDiff(APITest):
         self.check_equal(self.upload("/api/files/" + d,
                          "libboost-program-options-dev_1.49.0.1_i386.deb").status_code, 200)
 
-        self.check_equal(self.post_task("/api/repos/" + repos[-1] + "/file/" + d).json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repos[-1] + "/file/" + d)
+        self.check_task(task)
 
-        resp = self.post_task("/api/repos/" + repos[-1] + '/snapshots', json={'Name': snapshots[0]})
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/repos/" + repos[-1] + '/snapshots', json={'Name': snapshots[0]})
+        self.check_task(task)
 
-        resp = self.post_task("/api/snapshots", json={'Name': snapshots[1]})
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.post_task("/api/snapshots", json={'Name': snapshots[1]})
+        self.check_task(task)
 
         resp = self.get("/api/snapshots/" + snapshots[0] + "/diff/" + snapshots[1])
         self.check_equal(resp.status_code, 200)
@@ -302,19 +309,19 @@ class SnapshotsAPITestMerge(APITest):
 
         # create source snapshots
         for source in sources:
-            resp = self.post_task("/api/snapshots", json=source)
-            self.check_equal(resp.json()["State"], TASK_SUCCEEDED)
+            task = self.post_task("/api/snapshots", json=source)
+            self.check_task(task)
 
         # create merge snapshot
         merged_name = self.random_name()
-        resp = self.post_task(
+        task = self.post_task(
             "/api/snapshots/merge",
             json={
                 "Destination": merged_name,
                 "Sources": [source["Name"] for source in sources],
             },
         )
-        self.check_equal(resp.json()["State"], TASK_SUCCEEDED)
+        self.check_task(task)
 
         # check merge snapshot
         resp = self.get(f"/api/snapshots/{merged_name}")
@@ -329,9 +336,8 @@ class SnapshotsAPITestMerge(APITest):
         )
 
         # remove merge snapshot
-        self.check_equal(
-            self.delete_task(f"/api/snapshots/{merged_name}").json()["State"], TASK_SUCCEEDED
-        )
+        task = self.delete_task(f"/api/snapshots/{merged_name}")
+        self.check_task(task)
 
         # create merge snapshot without sources
         merged_name = self.random_name()
diff --git a/system/t12_api/tasks.py b/system/t12_api/tasks.py
index 42b17c98..8d393248 100644
--- a/system/t12_api/tasks.py
+++ b/system/t12_api/tasks.py
@@ -1,4 +1,4 @@
-from api_lib import TASK_SUCCEEDED, APITest
+from api_lib import APITest
 
 from .publish import DefaultSigningOptions
 
@@ -49,9 +49,8 @@ class TaskAPITestParallelTasks(APITest):
 
     def _wait_for_task(self, task_id):
         uri = "/api/tasks/%d/wait" % int(task_id)
-        resp = self.get(uri)
-        self.check_equal(resp.status_code, 200)
-        self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+        task = self.get(uri)
+        self.check_task(task)
 
     def _wait_for_all_tasks(self):
         resp = self.get("/api/tasks-wait")
@@ -103,6 +102,5 @@ class TaskAPITestParallelTasks(APITest):
         self._wait_for_all_tasks()
 
         for publish_task_id in publish_task_ids:
-            resp = self.get("/api/tasks/%d" % publish_task_id)
-            self.check_equal(resp.status_code, 200)
-            self.check_equal(resp.json()['State'], TASK_SUCCEEDED)
+            task = self.get("/api/tasks/%d" % publish_task_id)
+            self.check_task(task)
diff --git a/system/t12_api/unix_socket.py b/system/t12_api/unix_socket.py
index b14fe946..aa5ac2db 100644
--- a/system/t12_api/unix_socket.py
+++ b/system/t12_api/unix_socket.py
@@ -6,19 +6,28 @@ import urllib.parse
 import urllib.request
 
 from lib import BaseTest
+from api_lib import AptlyStream
 
 
 class UnixSocketAPITest(BaseTest):
     aptly_server = None
     socket_path = "/tmp/_aptly_test.sock"
     base_url = ("unix://%s" % socket_path)
+    aptly_out = None
+    debugOutput = True
 
     def prepare(self):
         if self.aptly_server is None:
-            self.aptly_server = self._start_process("aptly api serve -no-lock -listen=%s" % (self.base_url),)
+            UnixSocketAPITest.aptly_out = AptlyStream()
+            self.aptly_server = self._start_process("aptly api serve -no-lock -listen=%s" % (self.base_url), stdout=UnixSocketAPITest.aptly_out, stderr=UnixSocketAPITest.aptly_out)
             time.sleep(1)
+        else:
+            UnixSocketAPITest.aptly_out.clear()
         super(UnixSocketAPITest, self).prepare()
 
+    def debug_output(self):
+        return UnixSocketAPITest.aptly_out.get_contents()
+
     def shutdown(self):
         if self.aptly_server is not None:
             self.aptly_server.terminate()