tests: Improve tests as stderr and stdout may be returned in any order

tests/test_forkedsubprocess.py

@@ -86,8 +86,10 @@ class TestForkedSubprocess():
         process.run()
         process.wait()
 
-        assert process.output == ['test stdout', 'test stderr'], \
-            'Our test strings ["test stdout", "test stderr"] should be returned in the .output property'
+        assert 'test stdout' in process.output, \
+            'Our test strings "test stdout" should be returned in the .output property'
+        assert 'test stderr' in process.output, \
+            'Our test strings "test stderr" should be returned in the .output property'
         assert process.stdout == ['test stdout'], 'Our test string "test stdout" should of been returned in the .stdout property'
         assert process.stderr == ['test stderr'], 'Our test string "test stderr" should of been returned in the .stderr property'
         assert process.stderr == ['test stderr'], 'Our test string "test stderr" should of been returned in the .stderr property'