improve api tests and error output

show only relevant aptly logs if a test fails.
for async tasks, show task output, as it contains the error message.

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))