pytest: set rules to find test files and functions

1e06a5195b removed pytest.ini. Without the
ini file, pytest 3.x has suboptimal settings and no longer picks up all
test functions and test files.

Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Milan Kubik <mkubik@redhat.com>

ipatests/conftest.py

@@ -42,6 +42,12 @@ NO_RECURSE_DIRS = [
     'install/share'
 ]
 
+INIVALUES = {
+    'python_classes': ['test_', 'Test'],
+    'python_files': ['test_*.py'],
+    'python_functions': ['test_*'],
+}
+
 
 def pytest_configure(config):
     # add pytest markers
@@ -52,12 +58,10 @@ def pytest_configure(config):
     for norecursedir in NO_RECURSE_DIRS:
         config.addinivalue_line('norecursedirs', norecursedir)
 
-    # load test classes with these prefixes.
-    # addinivalue_line() adds duplicated entries.
-    python_classes = config.getini('python_classes')
-    for value in ['test_', 'Test']:
-        if value not in python_classes:
-            python_classes.append(value)
+    # addinivalue_line() adds duplicated entries and does not remove existing.
+    for name, values in INIVALUES.items():
+        current = config.getini(name)
+        current[:] = values
 
     # set default JUnit prefix
     if config.option.junitprefix is None: