Add a test about claiming a plugin is a file tracer, when it is not.

1 files changed, 13 insertions, 0 deletions

diff --git a/tests/test_plugins.py b/tests/test_plugins.py
index 798e04ab..2f58eceb 100644
--- a/tests/test_plugins.py
+++ b/tests/test_plugins.py
@@ -471,6 +471,9 @@ class BadPluginTest(FileTracerTest):
         `our_error` is True if the error reported to the user will be an
         explicit error in our test code, marked with an # Oh noes! comment.
 
+        The plugin will be disabled, and we check that a warning is output
+        explaining why.
+
         """
         self.make_file("simple.py", """\
             import other, another
@@ -511,6 +514,16 @@ class BadPluginTest(FileTracerTest):
         warnings = stderr.count(msg)
         self.assertEqual(warnings, 1)
 
+    def test_file_tracer_has_no_file_tracer_method(self):
+        self.make_file("bad_plugin.py", """\
+            class Plugin(object):
+                pass
+
+            def coverage_init(reg, options):
+                reg.add_file_tracer(Plugin())
+            """)
+        self.run_bad_plugin("bad_plugin", "Plugin", our_error=False)
+
     def test_file_tracer_fails(self):
         self.make_file("bad_plugin.py", """\
             import coverage.plugin