python-pytest: Fix conflict error as following:

file /usr/bin/py.test conflicts between attempted installs of python3-pytest-3.4.2-r0 and python-pytest-3.4.2-r0
  file /usr/bin/pytest conflicts between attempted installs of python3-pytest-3.4.2-r0 and python-pytest-3.4.2-r0

Signed-off-by: Lei Maohui <leimaohui@cn.fujitsu.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-python/recipes-devtools/python/python-pytest.inc

@@ -9,6 +9,8 @@ SRC_URI[sha256sum] = "117bad36c1a787e1a8a659df35de53ba05f9f3398fb9e4ac17e80ad590
 SRC_URI_append = " file://0001-setup.py-remove-the-setup_requires-for-setuptools-scm.patch \
                    file://pytest_version_fix.patch "
 
+inherit update-alternatives
+
 RDEPENDS_${PN}_class-target += " \
     ${PYTHON_PN}-attrs \
     ${PYTHON_PN}-debugger \
@@ -22,4 +24,12 @@ RDEPENDS_${PN}_class-target += " \
 
 FILESEXTRAPATHS_prepend := "${THISDIR}/python-pytest:"
 
+ALTERNATIVE_${PN} += "py.test pytest"
+
+NATIVE_LINK_NAME[pytest] = "${bindir}/pytest"
+ALTERNATIVE_TARGET[pytest] = "${bindir}/pytest"
+
+ALTERNATIVE_LINK_NAME[py.test] = "${bindir}/py.test"
+ALTERNATIVE_TARGET[py.test] = "${bindir}/py.test"
+
 BBCLASSEXTEND = "native nativesdk"

meta-python/recipes-devtools/python/python-pytest_3.4.2.bb

@@ -6,3 +6,4 @@ RDEPENDS_${PN}_class-target += " \
     ${PYTHON_PN}-compiler \
     ${PYTHON_PN}-funcsigs \
 "
+ALTERNATIVE_PRIORITY = "10"

meta-python/recipes-devtools/python/python3-pytest_3.4.2.bb

@@ -1,2 +1,4 @@
 inherit pypi setuptools3
 require python-pytest.inc
+
+ALTERNATIVE_PRIORITY = "100"