Fix Python 2 installation and CI failures (#227)

* Fix line length of a comment causing flake8 checks to fail
* Update the macOS VM to one supported by AzurePipelines (the existing one had been removed)
* Set max version of soupsieve on Python 2.7 otherwise an incompatible version is installed.

azure-pipelines.yml

@@ -37,19 +37,19 @@ jobs:
                     sendCoverage: "true"
                 mac_python_2_7:
                     python.version: "2.7"
-                    imageName: macos-10.13
+                    imageName: macOS-10.15
                     sendCoverage: "false"
                 mac_python_3_5:
                     python.version: "3.5"
-                    imageName: macos-10.13
+                    imageName: macOS-10.15
                     sendCoverage: "false"
                 mac_python_3_6:
                     python.version: "3.6"
-                    imageName: macos-10.13
+                    imageName: macOS-10.15
                     sendCoverage: "false"
                 mac_python_3_7:
                     python.version: "3.7"
-                    imageName: macos-10.13
+                    imageName: macOS-10.15
                     sendCoverage: "false"
                 windows_python_2_7:
                     python.version: "2.7"

setup.py

@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import os
+import sys
 from distutils.core import setup
 from setuptools import find_packages
 
@@ -38,6 +39,13 @@ def read(fname):
 with open(os.path.join(repository_dir, 'requirements.txt')) as fh:
     requirements = fh.readlines()
 
+# soupsieve is not a direct requirement of this package, but left to it's own
+# devices a version >= 2.0 is installed for Python 2 which is not compatible.
+# Therefore perform the installation of a compatible package before any other
+# packages are installed.
+if sys.version_info.major == 2:
+    requirements.insert(0, "soupsieve<2.0")
+
 with open(os.path.join(repository_dir, 'test_requirements.txt')) as fh:
     test_requirements = fh.readlines()
 

src/mbed_os_tools/detect/darwin.py

@@ -43,7 +43,8 @@ def _plist_from_popen(popen):
         return []
     try:
         try:
-            # Try simple and fast first if this fails fall back to the slower but better process
+            # Try simple and fast first if this fails fall back to the slower but
+            # more robust process.
             return loads(out)
         except ExpatError:
             # Beautiful soup ensures the XML is properly formed after it is parsed