Add an explicit test for backward compatibility with "config.slaveinput"

Related to #234

testing/acceptance_test.py

@@ -192,6 +192,20 @@ class TestDistribution:
         ])
         assert dest.join(subdir.basename).check(dir=1)
 
+    def test_backward_compatibility_worker_terminology(self, testdir):
+        """Ensure that we still support "config.slaveinput" for backward compatibility (#234).
+
+        Keep in mind that removing this compatibility will break a ton of plugins and user code.
+        """
+        testdir.makepyfile("""
+            def test(pytestconfig):
+                assert hasattr(pytestconfig, 'slaveinput')
+                assert hasattr(pytestconfig, 'workerinput')
+        """)
+        result = testdir.runpytest("-n1")
+        result.stdout.fnmatch_lines("*1 passed*")
+        assert result.ret == 0
+
     def test_data_exchange(self, testdir):
         testdir.makeconftest("""
             # This hook only called on master.