Make sure informative file name make it to the XML report

pytest_black.py

@@ -41,7 +41,7 @@ def pytest_unconfigure(config):
 class BlackItem(pytest.Item, pytest.File):
     def __init__(self, path, parent):
         super(BlackItem, self).__init__(path, parent)
-        self._nodeid += "::BLACK"
+        self._nodeid += "-BLACK"
         self.add_marker("black")
         try:
             with open("pyproject.toml") as toml_file:

tests/test_black.py

@@ -1,4 +1,6 @@
 # -*- coding: utf-8 -*-
+from xml import dom
+from xml.dom.minidom import parse
 
 
 def test_help_message(testdir):
@@ -116,3 +118,15 @@ def hello():
 
     result = testdir.runpytest("--black")
     result.assert_outcomes(skipped=0, passed=1)
+
+
+def test_names(testdir):
+    """Assert test names are informative about what file was tested
+    """
+    file = testdir.makepyfile('def hello():\n    print("Hello, world!")')
+    file.write(data="\n", mode="a")
+
+    testdir.runpytest("--black", "--junit-xml=test-output.xml")
+    dom = parse((testdir.tmpdir / "test-output.xml").open())
+    test_case = dom.getElementsByTagName("testcase")[0]
+    assert "test_names.py" in test_case.getAttribute("name")