COVERAGE_RCFILE can specify the config file location. #650

3 files changed, 27 insertions, 1 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index ced7026..85db3b2 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -17,10 +17,15 @@ Change history for Coverage.py
 Unreleased (might become 4.6)
 -----------------------------
 
+- The location of the configuration file can now be specified with a
+  `COVERAGE_RCFILE` environment variable, as requested in `issue 650`_.
+
 - A new warning (already-imported) is issued if measurable files have already
   been imported before coverage.py started measurement.  See
   :ref:`cmd_warnings` for more information.
 
+.. _issue 650: https://bitbucket.org/ned/coveragepy/issues/650/allow-setting-configuration-file-location
+
 
 .. _changes_451:
 
diff --git a/coverage/config.py b/coverage/config.py
index 260dafd..285cb21 100644
--- a/coverage/config.py
+++ b/coverage/config.py
@@ -447,6 +447,12 @@ def config_files_to_try(config_file):
         config_file = True
     specified_file = (config_file is not True)
     if not specified_file:
+        # No file was specified. Check COVERAGE_RCFILE.
+        config_file = os.environ.get('COVERAGE_RCFILE')
+        if config_file:
+            specified_file = True
+    if not specified_file:
+        # Still no file specified. Default to .coveragerc
         config_file = ".coveragerc"
     files_to_try = [
         (config_file, True, specified_file),
@@ -483,7 +489,7 @@ def read_coverage_config(config_file, **kwargs):
             config_read = config.from_file(fname, our_file=our_file)
             if config_read:
                 break
-            if our_file and specified_file:
+            if specified_file:
                 raise CoverageException("Couldn't read '%s' as a config file" % fname)
 
     # 3) from environment variables:
diff --git a/tests/test_config.py b/tests/test_config.py
index 0b4d40b..bbfa467 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -103,6 +103,21 @@ class ConfigTest(CoverageTest):
         cov = coverage.Coverage()
         self.assertEqual(cov.config.debug, ["dataio", "pids", "callers", "fooey"])
 
+    def test_rcfile_from_environment(self):
+        self.make_file("here.ini", """\
+            [run]
+            data_file = overthere.dat
+            """)
+        self.set_environ("COVERAGE_RCFILE", "here.ini")
+        cov = coverage.Coverage()
+        self.assertEqual(cov.config.data_file, "overthere.dat")
+
+    def test_missing_rcfile_from_environment(self):
+        self.set_environ("COVERAGE_RCFILE", "nowhere.ini")
+        msg = "Couldn't read 'nowhere.ini' as a config file"
+        with self.assertRaisesRegex(CoverageException, msg):
+            coverage.Coverage()
+
     def test_parse_errors(self):
         # Im-parsable values raise CoverageException, with details.
         bad_configs_and_msgs = [