Added failing test for source with trailing slash

This test is nearly identical to the one above it, with the only
change being the source that is used. This may end up turning into
a fixture instead if the tests end up being identical after the
fix is made.

Author: kevin-brown

tests/test_xml.py

@@ -320,7 +320,7 @@ def test_accented_directory(self) -> None:
 
     def test_no_duplicate_packages(self) -> None:
         self.make_file(
-            "namespace/package/__init__.py", 
+            "namespace/package/__init__.py",
             "from . import sample; from . import test; from .subpackage import test"
         )
         self.make_file("namespace/package/sample.py", "print('package.sample')")
@@ -489,6 +489,19 @@ def test_relative_source(self) -> None:
         elts = dom.findall(".//sources/source")
         assert [elt.text for elt in elts] == ["src"]
 
+    def test_relative_source_trailing_slash(self) -> None:
+        self.make_file("src/mod.py", "print(17)")
+        cov = coverage.Coverage(source=["src/"])
+        cov.set_option("run:relative_files", True)
+        self.start_import_stop(cov, "mod", modfile="src/mod.py")
+        cov.xml_report()
+
+        with open("coverage.xml") as x:
+            print(x.read())
+        dom = ElementTree.parse("coverage.xml")
+        elts = dom.findall(".//sources/source")
+        assert [elt.text for elt in elts] == ["src"]
+
 
 def compare_xml(expected: str, actual: str, actual_extra: bool = False) -> None:
     """Specialized compare function for our XML files."""