refactor(test): reorg the parser tests in prep for moving more here

tests/test_parser.py

@@ -17,20 +17,24 @@
 from tests.helpers import arcz_to_arcs, xfail_pypy38
 
 
-class PythonParserTest(CoverageTest):
+class PythonParserTestBase(CoverageTest):
     """Tests for coverage.py's Python code parsing."""
 
     run_in_temp_dir = False
 
-    def parse_source(self, text: str) -> PythonParser:
+    def parse_text(self, text: str) -> PythonParser:
         """Parse `text` as source, and return the `PythonParser` used."""
         text = textwrap.dedent(text)
         parser = PythonParser(text=text, exclude="nocover")
         parser.parse_source()
         return parser
 
+
+class PythonParserTest(PythonParserTestBase):
+    """Tests of coverage.parser."""
+
     def test_exit_counts(self) -> None:
-        parser = self.parse_source("""\
+        parser = self.parse_text("""\
             # check some basic branch counting
             class Foo:
                 def foo(self, a):
@@ -48,7 +52,7 @@ class Bar:
 
     def test_generator_exit_counts(self) -> None:
         # https://github.com/nedbat/coveragepy/issues/324
-        parser = self.parse_source("""\
+        parser = self.parse_text("""\
             def gen(input):
                 for n in inp:
                     yield (i * 2 for i in range(n))
@@ -63,7 +67,7 @@ def gen(input):
         }
 
     def test_try_except(self) -> None:
-        parser = self.parse_source("""\
+        parser = self.parse_text("""\
             try:
                 a = 2
             except ValueError:
@@ -79,7 +83,7 @@ def test_try_except(self) -> None:
         }
 
     def test_excluded_classes(self) -> None:
-        parser = self.parse_source("""\
+        parser = self.parse_text("""\
             class Foo:
                 def __init__(self):
                     pass
@@ -93,15 +97,15 @@ class Bar:
         }
 
     def test_missing_branch_to_excluded_code(self) -> None:
-        parser = self.parse_source("""\
+        parser = self.parse_text("""\
             if fooey:
                 a = 2
             else:   # nocover
                 a = 4
             b = 5
             """)
         assert parser.exit_counts() == { 1:1, 2:1, 5:1 }
-        parser = self.parse_source("""\
+        parser = self.parse_text("""\
             def foo():
                 if fooey:
                     a = 3
@@ -110,7 +114,7 @@ def foo():
             b = 6
             """)
         assert parser.exit_counts() == { 1:1, 2:2, 3:1, 5:1, 6:1 }
-        parser = self.parse_source("""\
+        parser = self.parse_text("""\
             def foo():
                 if fooey:
                     a = 3
@@ -126,7 +130,7 @@ def test_indentation_error(self) -> None:
             "'unindent does not match any outer indentation level.*' at line 3"
         )
         with pytest.raises(NotPython, match=msg):
-            _ = self.parse_source("""\
+            _ = self.parse_text("""\
                 0 spaces
                   2
                  1
@@ -143,11 +147,58 @@ def test_token_error(self) -> None:
             + r"' at line 1"
         )
         with pytest.raises(NotPython, match=msg):
-            _ = self.parse_source("'''")
+            _ = self.parse_text("'''")
+
+    def test_empty_decorated_function(self) -> None:
+        parser = self.parse_text("""\
+            def decorator(func):
+                return func
+
+            @decorator
+            def foo(self):
+                '''Docstring'''
+
+            @decorator
+            def bar(self):
+                pass
+            """)
+
+        expected_statements = {1, 2, 4, 5, 8, 9, 10}
+        expected_arcs = set(arcz_to_arcs(".1 14 45 58 89 9.  .2 2.  -8A A-8"))
+        expected_exits = {1: 1, 2: 1, 4: 1, 5: 1, 8: 1, 9: 1, 10: 1}
+
+        if env.PYBEHAVIOR.docstring_only_function:
+            # 3.7 changed how functions with only docstrings are numbered.
+            expected_arcs.update(set(arcz_to_arcs("-46 6-4")))
+            expected_exits.update({6: 1})
+
+        if env.PYBEHAVIOR.trace_decorator_line_again:
+            expected_arcs.update(set(arcz_to_arcs("54 98")))
+            expected_exits.update({9: 2, 5: 2})
+
+        assert expected_statements == parser.statements
+        assert expected_arcs == parser.arcs()
+        assert expected_exits == parser.exit_counts()
+
+    def test_fuzzed_double_parse(self) -> None:
+        # https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=50381
+        # The second parse used to raise `TypeError: 'NoneType' object is not iterable`
+        msg = (
+            r"(EOF in multi-line statement)"        # before 3.12.0b1
+            + r"|(unmatched ']')"                   # after 3.12.0b1
+        )
+        with pytest.raises(NotPython, match=msg):
+            self.parse_text("]")
+        with pytest.raises(NotPython, match=msg):
+            self.parse_text("]")
+
+
+class ExclusionParserTest(PythonParserTestBase):
+    """Tests for the exclusion code in PythonParser."""
 
     @xfail_pypy38
     def test_decorator_pragmas(self) -> None:
-        parser = self.parse_source("""\
+        parser = self.parse_text("""\
             # 1
 
             @foo(3)                     # nocover
@@ -183,7 +234,7 @@ def func(x=25):
     def test_decorator_pragmas_with_colons(self) -> None:
         # A colon in a decorator expression would confuse the parser,
         # ending the exclusion of the decorated function.
-        parser = self.parse_source("""\
+        parser = self.parse_text("""\
             @decorate(X)        # nocover
             @decorate("Hello"[2])
             def f():
@@ -199,7 +250,7 @@ def g():
         assert parser.statements == set()
 
     def test_class_decorator_pragmas(self) -> None:
-        parser = self.parse_source("""\
+        parser = self.parse_text("""\
             class Foo(object):
                 def __init__(self):
                     self.x = 3
@@ -212,61 +263,10 @@ def __init__(self):
         assert parser.raw_statements == {1, 2, 3, 5, 6, 7, 8}
         assert parser.statements == {1, 2, 3}
 
-    def test_empty_decorated_function(self) -> None:
-        parser = self.parse_source("""\
-            def decorator(func):
-                return func
-
-            @decorator
-            def foo(self):
-                '''Docstring'''
-
-            @decorator
-            def bar(self):
-                pass
-            """)
-
-        expected_statements = {1, 2, 4, 5, 8, 9, 10}
-        expected_arcs = set(arcz_to_arcs(".1 14 45 58 89 9.  .2 2.  -8A A-8"))
-        expected_exits = {1: 1, 2: 1, 4: 1, 5: 1, 8: 1, 9: 1, 10: 1}
-
-        if env.PYBEHAVIOR.docstring_only_function:
-            # 3.7 changed how functions with only docstrings are numbered.
-            expected_arcs.update(set(arcz_to_arcs("-46 6-4")))
-            expected_exits.update({6: 1})
-
-        if env.PYBEHAVIOR.trace_decorator_line_again:
-            expected_arcs.update(set(arcz_to_arcs("54 98")))
-            expected_exits.update({9: 2, 5: 2})
 
-        assert expected_statements == parser.statements
-        assert expected_arcs == parser.arcs()
-        assert expected_exits == parser.exit_counts()
-
-    def test_fuzzed_double_parse(self) -> None:
-        # https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=50381
-        # The second parse used to raise `TypeError: 'NoneType' object is not iterable`
-        msg = (
-            r"(EOF in multi-line statement)"        # before 3.12.0b1
-            + r"|(unmatched ']')"                   # after 3.12.0b1
-        )
-        with pytest.raises(NotPython, match=msg):
-            self.parse_source("]")
-        with pytest.raises(NotPython, match=msg):
-            self.parse_source("]")
-
-
-class ParserMissingArcDescriptionTest(CoverageTest):
+class ParserMissingArcDescriptionTest(PythonParserTestBase):
     """Tests for PythonParser.missing_arc_description."""
 
-    run_in_temp_dir = False
-
-    def parse_text(self, source: str) -> PythonParser:
-        """Parse Python source, and return the parser object."""
-        parser = PythonParser(text=textwrap.dedent(source))
-        parser.parse_source()
-        return parser
-
     def test_missing_arc_description(self) -> None:
         # This code is never run, so the actual values don't matter.
         parser = self.parse_text("""\