Merged in c_henz/pytest/explicit-ini-filename (pull request #175)

Implement the "-c" command line switch that allows to explicitly specifiy the config file to load.

_pytest/config.py

@@ -685,7 +685,15 @@ class Config(object):
     pytest_load_initial_conftests.trylast = True
 
     def _initini(self, args):
-        self.inicfg = getcfg(args, ["pytest.ini", "tox.ini", "setup.cfg"])
+        parsed_args = self._parser.parse_known_args(args)
+        if parsed_args.inifilename:
+            iniconfig = py.iniconfig.IniConfig(parsed_args.inifilename)
+            if 'pytest' in iniconfig.sections:
+                self.inicfg = iniconfig['pytest']
+            else:
+                self.inicfg = {}
+        else:
+            self.inicfg = getcfg(args, ["pytest.ini", "tox.ini", "setup.cfg"])
         self._parser.addini('addopts', 'extra command line options', 'args')
         self._parser.addini('minversion', 'minimally required pytest version')
 

_pytest/main.py

@@ -38,6 +38,8 @@ def pytest_addoption(parser):
                help="exit after first num failures or errors.")
     group._addoption('--strict', action="store_true",
                help="run pytest in strict mode, warnings become errors.")
+    group._addoption("-c", metavar="file", type=str, dest="inifilename",
+               help="load configuration from `file` instead of trying to locate one of the implicit configuration files.")
 
     group = parser.getgroup("collect", "collection")
     group.addoption('--collectonly', '--collect-only', action="store_true",

testing/test_config.py

@@ -79,6 +79,21 @@ class TestConfigCmdlineParsing:
         config = testdir.parseconfig()
         pytest.raises(AssertionError, lambda: config.parse([]))
 
+    def test_explicitly_specified_config_file_is_loaded(self, testdir):
+        testdir.makeconftest("""
+            def pytest_addoption(parser):
+                parser.addini("custom", "")
+        """)
+        testdir.makeini("""
+            [pytest]
+            custom = 0
+        """)
+        testdir.makefile(".cfg", custom = """
+            [pytest]
+            custom = 1
+        """)
+        config = testdir.parseconfig("-c", "custom.cfg")
+        assert config.getini("custom") == "1"
 
 class TestConfigAPI:
     def test_config_trace(self, testdir):