Add coverage

tools/telemetry/third_party/coverage/tests/test_process.py

+# coding: utf8
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt
+
+"""Tests for process behavior of coverage.py."""
+
+import glob
+import os
+import os.path
+import re
+import sys
+import textwrap
+
+import coverage
+from coverage import env, CoverageData
+
+from tests.coveragetest import CoverageTest
+
+HERE = os.path.dirname(__file__)
+
+
+class ProcessTest(CoverageTest):
+    """Tests of the per-process behavior of coverage.py."""
+
+    def number_of_data_files(self):
+        """Return the number of coverage data files in this directory."""
+        num = 0
+        for f in os.listdir('.'):
+            if f.startswith('.coverage.') or f == '.coverage':
+                num += 1
+        return num
+
+    def test_save_on_exit(self):
+        self.make_file("mycode.py", """\
+            h = "Hello"
+            w = "world"
+            """)
+
+        self.assert_doesnt_exist(".coverage")
+        self.run_command("coverage run mycode.py")
+        self.assert_exists(".coverage")
+
+    def test_environment(self):
+        # Checks that we can import modules from the test directory at all!
+        self.make_file("mycode.py", """\
+            import covmod1
+            import covmodzip1
+            a = 1
+            print('done')
+            """)
+
+        self.assert_doesnt_exist(".coverage")
+        out = self.run_command("coverage run mycode.py")
+        self.assert_exists(".coverage")
+        self.assertEqual(out, 'done\n')
+
+    def make_b_or_c_py(self):
+        """Create b_or_c.py, used in a few of these tests."""
+        self.make_file("b_or_c.py", """\
+            import sys
+            a = 1
+            if sys.argv[1] == 'b':
+                b = 1
+            else:
+                c = 1
+            d = 1
+            print('done')
+            """)
+
+    def test_combine_parallel_data(self):
+        self.make_b_or_c_py()
+        out = self.run_command("coverage run -p b_or_c.py b")
+        self.assertEqual(out, 'done\n')
+        self.assert_doesnt_exist(".coverage")
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        out = self.run_command("coverage run -p b_or_c.py c")
+        self.assertEqual(out, 'done\n')
+        self.assert_doesnt_exist(".coverage")
+
+        # After two -p runs, there should be two .coverage.machine.123 files.
+        self.assertEqual(self.number_of_data_files(), 2)
+
+        # Combine the parallel coverage data files into .coverage .
+        self.run_command("coverage combine")
+        self.assert_exists(".coverage")
+
+        # After combining, there should be only the .coverage file.
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        # Read the coverage file and see that b_or_c.py has all 7 lines
+        # executed.
+        data = coverage.CoverageData()
+        data.read_file(".coverage")
+        self.assertEqual(data.line_counts()['b_or_c.py'], 7)
+
+    def test_combine_parallel_data_in_two_steps(self):
+        self.make_b_or_c_py()
+
+        out = self.run_command("coverage run -p b_or_c.py b")
+        self.assertEqual(out, 'done\n')
+        self.assert_doesnt_exist(".coverage")
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        # Combine the (one) parallel coverage data file into .coverage .
+        self.run_command("coverage combine")
+        self.assert_exists(".coverage")
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        out = self.run_command("coverage run -p b_or_c.py c")
+        self.assertEqual(out, 'done\n')
+        self.assert_exists(".coverage")
+        self.assertEqual(self.number_of_data_files(), 2)
+
+        # Combine the parallel coverage data files into .coverage .
+        self.run_command("coverage combine")
+        self.assert_exists(".coverage")
+
+        # After combining, there should be only the .coverage file.
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        # Read the coverage file and see that b_or_c.py has all 7 lines
+        # executed.
+        data = coverage.CoverageData()
+        data.read_file(".coverage")
+        self.assertEqual(data.line_counts()['b_or_c.py'], 7)
+
+    def test_append_data(self):
+        self.make_b_or_c_py()
+
+        out = self.run_command("coverage run b_or_c.py b")
+        self.assertEqual(out, 'done\n')
+        self.assert_exists(".coverage")
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        out = self.run_command("coverage run --append b_or_c.py c")
+        self.assertEqual(out, 'done\n')
+        self.assert_exists(".coverage")
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        # Read the coverage file and see that b_or_c.py has all 7 lines
+        # executed.
+        data = coverage.CoverageData()
+        data.read_file(".coverage")
+        self.assertEqual(data.line_counts()['b_or_c.py'], 7)
+
+    def test_append_data_with_different_file(self):
+        self.make_b_or_c_py()
+
+        self.make_file(".coveragerc", """\
+            [run]
+            data_file = .mycovdata
+            """)
+
+        out = self.run_command("coverage run b_or_c.py b")
+        self.assertEqual(out, 'done\n')
+        self.assert_doesnt_exist(".coverage")
+        self.assert_exists(".mycovdata")
+
+        out = self.run_command("coverage run --append b_or_c.py c")
+        self.assertEqual(out, 'done\n')
+        self.assert_doesnt_exist(".coverage")
+        self.assert_exists(".mycovdata")
+
+        # Read the coverage file and see that b_or_c.py has all 7 lines
+        # executed.
+        data = coverage.CoverageData()
+        data.read_file(".mycovdata")
+        self.assertEqual(data.line_counts()['b_or_c.py'], 7)
+
+    def test_append_can_create_a_data_file(self):
+        self.make_b_or_c_py()
+
+        out = self.run_command("coverage run --append b_or_c.py b")
+        self.assertEqual(out, 'done\n')
+        self.assert_exists(".coverage")
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        # Read the coverage file and see that b_or_c.py has only 6 lines
+        # executed.
+        data = coverage.CoverageData()
+        data.read_file(".coverage")
+        self.assertEqual(data.line_counts()['b_or_c.py'], 6)
+
+    def test_combine_with_rc(self):
+        self.make_b_or_c_py()
+
+        self.make_file(".coveragerc", """\
+            [run]
+            parallel = true
+            """)
+
+        out = self.run_command("coverage run b_or_c.py b")
+        self.assertEqual(out, 'done\n')
+        self.assert_doesnt_exist(".coverage")
+
+        out = self.run_command("coverage run b_or_c.py c")
+        self.assertEqual(out, 'done\n')
+        self.assert_doesnt_exist(".coverage")
+
+        # After two runs, there should be two .coverage.machine.123 files.
+        self.assertEqual(self.number_of_data_files(), 2)
+
+        # Combine the parallel coverage data files into .coverage .
+        self.run_command("coverage combine")
+        self.assert_exists(".coverage")
+        self.assert_exists(".coveragerc")
+
+        # After combining, there should be only the .coverage file.
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        # Read the coverage file and see that b_or_c.py has all 7 lines
+        # executed.
+        data = coverage.CoverageData()
+        data.read_file(".coverage")
+        self.assertEqual(data.line_counts()['b_or_c.py'], 7)
+
+        # Reporting should still work even with the .rc file
+        out = self.run_command("coverage report")
+        self.assertMultiLineEqual(out, textwrap.dedent("""\
+            Name        Stmts   Miss  Cover
+            -------------------------------
+            b_or_c.py       7      0   100%
+            """))
+
+    def test_combine_with_aliases(self):
+        self.make_file("d1/x.py", """\
+            a = 1
+            b = 2
+            print("%s %s" % (a, b))
+            """)
+
+        self.make_file("d2/x.py", """\
+            # 1
+            # 2
+            # 3
+            c = 4
+            d = 5
+            print("%s %s" % (c, d))
+            """)
+
+        self.make_file(".coveragerc", """\
+            [run]
+            parallel = True
+
+            [paths]
+            source =
+                src
+                */d1
+                */d2
+            """)
+
+        out = self.run_command("coverage run " + os.path.normpath("d1/x.py"))
+        self.assertEqual(out, '1 2\n')
+        out = self.run_command("coverage run " + os.path.normpath("d2/x.py"))
+        self.assertEqual(out, '4 5\n')
+
+        self.assertEqual(self.number_of_data_files(), 2)
+
+        self.run_command("coverage combine")
+        self.assert_exists(".coverage")
+
+        # After combining, there should be only the .coverage file.
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        # Read the coverage data file and see that the two different x.py
+        # files have been combined together.
+        data = coverage.CoverageData()
+        data.read_file(".coverage")
+        summary = data.line_counts(fullpath=True)
+        self.assertEqual(len(summary), 1)
+        actual = os.path.normcase(os.path.abspath(list(summary.keys())[0]))
+        expected = os.path.normcase(os.path.abspath('src/x.py'))
+        self.assertEqual(actual, expected)
+        self.assertEqual(list(summary.values())[0], 6)
+
+    def test_erase_parallel(self):
+        self.make_file(".coveragerc", """\
+            [run]
+            data_file = data.dat
+            parallel = True
+            """)
+        self.make_file("data.dat")
+        self.make_file("data.dat.fooey")
+        self.make_file("data.dat.gooey")
+        self.make_file(".coverage")
+
+        self.run_command("coverage erase")
+        self.assert_doesnt_exist("data.dat")
+        self.assert_doesnt_exist("data.dat.fooey")
+        self.assert_doesnt_exist("data.dat.gooey")
+        self.assert_exists(".coverage")
+
+    def test_missing_source_file(self):
+        # Check what happens if the source is missing when reporting happens.
+        self.make_file("fleeting.py", """\
+            s = 'goodbye, cruel world!'
+            """)
+
+        self.run_command("coverage run fleeting.py")
+        os.remove("fleeting.py")
+        out = self.run_command("coverage html -d htmlcov")
+        self.assertRegex(out, "No source for code: '.*fleeting.py'")
+        self.assertNotIn("Traceback", out)
+
+        # It happens that the code paths are different for *.py and other
+        # files, so try again with no extension.
+        self.make_file("fleeting", """\
+            s = 'goodbye, cruel world!'
+            """)
+
+        self.run_command("coverage run fleeting")
+        os.remove("fleeting")
+        status, out = self.run_command_status("coverage html -d htmlcov")
+        self.assertRegex(out, "No source for code: '.*fleeting'")
+        self.assertNotIn("Traceback", out)
+        self.assertEqual(status, 1)
+
+    def test_running_missing_file(self):
+        status, out = self.run_command_status("coverage run xyzzy.py")
+        self.assertRegex(out, "No file to run: .*xyzzy.py")
+        self.assertNotIn("raceback", out)
+        self.assertNotIn("rror", out)
+        self.assertEqual(status, 1)
+
+    def test_code_throws(self):
+        self.make_file("throw.py", """\
+            def f1():
+                raise Exception("hey!")
+
+            def f2():
+                f1()
+
+            f2()
+            """)
+
+        # The important thing is for "coverage run" and "python" to report the
+        # same traceback.
+        status, out = self.run_command_status("coverage run throw.py")
+        out2 = self.run_command("python throw.py")
+        if env.PYPY:
+            # Pypy has an extra frame in the traceback for some reason
+            lines2 = out2.splitlines()
+            out2 = "".join(l+"\n" for l in lines2 if "toplevel" not in l)
+        self.assertMultiLineEqual(out, out2)
+
+        # But also make sure that the output is what we expect.
+        self.assertIn('File "throw.py", line 5, in f2', out)
+        self.assertIn('raise Exception("hey!")', out)
+        self.assertNotIn('coverage', out)
+        self.assertEqual(status, 1)
+
+    def test_code_exits(self):
+        self.make_file("exit.py", """\
+            import sys
+            def f1():
+                print("about to exit..")
+                sys.exit(17)
+
+            def f2():
+                f1()
+
+            f2()
+            """)
+
+        # The important thing is for "coverage run" and "python" to have the
+        # same output.  No traceback.
+        status, out = self.run_command_status("coverage run exit.py")
+        status2, out2 = self.run_command_status("python exit.py")
+        self.assertMultiLineEqual(out, out2)
+        self.assertMultiLineEqual(out, "about to exit..\n")
+        self.assertEqual(status, status2)
+        self.assertEqual(status, 17)
+
+    def test_code_exits_no_arg(self):
+        self.make_file("exit_none.py", """\
+            import sys
+            def f1():
+                print("about to exit quietly..")
+                sys.exit()
+
+            f1()
+            """)
+        status, out = self.run_command_status("coverage run exit_none.py")
+        status2, out2 = self.run_command_status("python exit_none.py")
+        self.assertMultiLineEqual(out, out2)
+        self.assertMultiLineEqual(out, "about to exit quietly..\n")
+        self.assertEqual(status, status2)
+        self.assertEqual(status, 0)
+
+    def test_coverage_run_is_like_python(self):
+        tryfile = os.path.join(HERE, "try_execfile.py")
+        with open(tryfile) as f:
+            self.make_file("run_me.py", f.read())
+        out_cov = self.run_command("coverage run run_me.py")
+        out_py = self.run_command("python run_me.py")
+        self.assertMultiLineEqual(out_cov, out_py)
+
+    def test_coverage_run_dashm_is_like_python_dashm(self):
+        # These -m commands assume the coverage tree is on the path.
+        out_cov = self.run_command("coverage run -m tests.try_execfile")
+        out_py = self.run_command("python -m tests.try_execfile")
+        self.assertMultiLineEqual(out_cov, out_py)
+
+    def test_coverage_run_dir_is_like_python_dir(self):
+        tryfile = os.path.join(HERE, "try_execfile.py")
+        with open(tryfile) as f:
+            self.make_file("with_main/__main__.py", f.read())
+        out_cov = self.run_command("coverage run with_main")
+        out_py = self.run_command("python with_main")
+
+        # The coverage.py results are not identical to the Python results, and
+        # I don't know why.  For now, ignore those failures. If someone finds
+        # a real problem with the discrepancies, we can work on it some more.
+        ignored = r"__file__|__loader__|__package__"
+        # PyPy includes the current directory in the path when running a
+        # directory, while CPython and coverage.py do not.  Exclude that from
+        # the comparison also...
+        if env.PYPY:
+            ignored += "|"+re.escape(os.getcwd())
+        out_cov = remove_matching_lines(out_cov, ignored)
+        out_py = remove_matching_lines(out_py, ignored)
+        self.assertMultiLineEqual(out_cov, out_py)
+
+    def test_coverage_run_dashm_equal_to_doubledashsource(self):
+        """regression test for #328
+
+        When imported by -m, a module's __name__ is __main__, but we need the
+        --source machinery to know and respect the original name.
+        """
+        # These -m commands assume the coverage tree is on the path.
+        out_cov = self.run_command(
+            "coverage run --source tests.try_execfile -m tests.try_execfile"
+        )
+        out_py = self.run_command("python -m tests.try_execfile")
+        self.assertMultiLineEqual(out_cov, out_py)
+
+    def test_coverage_run_dashm_superset_of_doubledashsource(self):
+        """Edge case: --source foo -m foo.bar"""
+        # These -m commands assume the coverage tree is on the path.
+        out_cov = self.run_command(
+            "coverage run --source tests -m tests.try_execfile"
+        )
+        out_py = self.run_command("python -m tests.try_execfile")
+        self.assertMultiLineEqual(out_cov, out_py)
+
+        st, out = self.run_command_status("coverage report")
+        self.assertEqual(st, 0)
+        self.assertEqual(self.line_count(out), 6, out)
+
+    def test_coverage_run_script_imports_doubledashsource(self):
+        # This file imports try_execfile, which compiles it to .pyc, so the
+        # first run will have __file__ == "try_execfile.py" and the second will
+        # have __file__ == "try_execfile.pyc", which throws off the comparison.
+        # Setting dont_write_bytecode True stops the compilation to .pyc and
+        # keeps the test working.
+        self.make_file("myscript", """\
+            import sys; sys.dont_write_bytecode = True
+            import tests.try_execfile
+            """)
+
+        # These -m commands assume the coverage tree is on the path.
+        out_cov = self.run_command(
+            "coverage run --source tests myscript"
+        )
+        out_py = self.run_command("python myscript")
+        self.assertMultiLineEqual(out_cov, out_py)
+
+        st, out = self.run_command_status("coverage report")
+        self.assertEqual(st, 0)
+        self.assertEqual(self.line_count(out), 6, out)
+
+    def test_coverage_run_dashm_is_like_python_dashm_off_path(self):
+        # https://bitbucket.org/ned/coveragepy/issue/242
+        tryfile = os.path.join(HERE, "try_execfile.py")
+        self.make_file("sub/__init__.py", "")
+        with open(tryfile) as f:
+            self.make_file("sub/run_me.py", f.read())
+        out_cov = self.run_command("coverage run -m sub.run_me")
+        out_py = self.run_command("python -m sub.run_me")
+        self.assertMultiLineEqual(out_cov, out_py)
+
+    def test_coverage_run_dashm_is_like_python_dashm_with__main__207(self):
+        if sys.version_info < (2, 7):
+            # Coverage.py isn't bug-for-bug compatible in the behavior of -m for
+            # Pythons < 2.7
+            self.skip("-m doesn't work the same < Python 2.7")
+        # https://bitbucket.org/ned/coveragepy/issue/207
+        self.make_file("package/__init__.py", "print('init')")
+        self.make_file("package/__main__.py", "print('main')")
+        out_cov = self.run_command("coverage run -m package")
+        out_py = self.run_command("python -m package")
+        self.assertMultiLineEqual(out_cov, out_py)
+
+    def test_fork(self):
+        if not hasattr(os, 'fork'):
+            self.skip("Can't test os.fork since it doesn't exist.")
+
+        self.make_file("fork.py", """\
+            import os
+
+            def child():
+                print('Child!')
+
+            def main():
+                ret = os.fork()
+
+                if ret == 0:
+                    child()
+                else:
+                    os.waitpid(ret, 0)
+
+            main()
+            """)
+
+        out = self.run_command("coverage run -p fork.py")
+        self.assertEqual(out, 'Child!\n')
+        self.assert_doesnt_exist(".coverage")
+
+        # After running the forking program, there should be two
+        # .coverage.machine.123 files.
+        self.assertEqual(self.number_of_data_files(), 2)
+
+        # Combine the parallel coverage data files into .coverage .
+        self.run_command("coverage combine")
+        self.assert_exists(".coverage")
+
+        # After combining, there should be only the .coverage file.
+        self.assertEqual(self.number_of_data_files(), 1)
+
+        # Read the coverage file and see that b_or_c.py has all 7 lines
+        # executed.
+        data = coverage.CoverageData()
+        data.read_file(".coverage")
+        self.assertEqual(data.line_counts()['fork.py'], 9)
+
+    def test_warnings(self):
+        self.make_file("hello.py", """\
+            import sys, os
+            print("Hello")
+            """)
+        out = self.run_command("coverage run --source=sys,xyzzy,quux hello.py")
+
+        self.assertIn("Hello\n", out)
+        self.assertIn(textwrap.dedent("""\
+            Coverage.py warning: Module sys has no Python source.
+            Coverage.py warning: Module xyzzy was never imported.
+            Coverage.py warning: Module quux was never imported.
+            Coverage.py warning: No data was collected.
+            """), out)
+
+    def test_warnings_during_reporting(self):
+        # While fixing issue #224, the warnings were being printed far too
+        # often.  Make sure they're not any more.
+        self.make_file("hello.py", """\
+            import sys, os, the_other
+            print("Hello")
+            """)
+        self.make_file("the_other.py", """\
+            print("What?")
+            """)
+        self.make_file(".coveragerc", """\
+            [run]
+            source =
+                .
+                xyzzy
+            """)
+
+        self.run_command("coverage run hello.py")
+        out = self.run_command("coverage html")
+        self.assertEqual(out.count("Module xyzzy was never imported."), 0)
+
+    def test_warnings_if_never_run(self):
+        out = self.run_command("coverage run i_dont_exist.py")
+        self.assertIn("No file to run: 'i_dont_exist.py'", out)
+        self.assertNotIn("warning", out)
+        self.assertNotIn("Exception", out)
+
+        out = self.run_command("coverage run -m no_such_module")
+        self.assertTrue(
+            ("No module named no_such_module" in out) or
+            ("No module named 'no_such_module'" in out)
+            )
+        self.assertNotIn("warning", out)
+        self.assertNotIn("Exception", out)
+
+    def test_warnings_trace_function_changed_with_threads(self):
+        # https://bitbucket.org/ned/coveragepy/issue/164
+        self.make_file("bug164.py", """\
+            import threading
+            import time
+
+            class MyThread (threading.Thread):
+                def run(self):
+                    print("Hello")
+
+            thr = MyThread()
+            thr.start()
+            thr.join()
+            """)
+        out = self.run_command("coverage run --timid bug164.py")
+
+        self.assertIn("Hello\n", out)
+        self.assertNotIn("warning", out)
+
+    def test_warning_trace_function_changed(self):
+        self.make_file("settrace.py", """\
+            import sys
+            print("Hello")
+            sys.settrace(None)
+            print("Goodbye")
+            """)
+        out = self.run_command("coverage run --timid settrace.py")
+        self.assertIn("Hello\n", out)
+        self.assertIn("Goodbye\n", out)
+
+        self.assertIn("Trace function changed", out)
+
+    def test_note(self):
+        self.make_file(".coveragerc", """\
+            [run]
+            data_file = mydata.dat
+            note = These are musical notes: ♫𝅗𝅥♩
+            """)
+        self.make_file("simple.py", """print('hello')""")
+        self.run_command("coverage run simple.py")
+
+        data = CoverageData()
+        data.read_file("mydata.dat")
+        infos = data.run_infos()
+        self.assertEqual(len(infos), 1)
+        self.assertEqual(infos[0]['note'], u"These are musical notes: ♫𝅗𝅥♩")
+
+    def test_fullcoverage(self):                        # pragma: not covered
+        if env.PY2:             # This doesn't work on Python 2.
+            self.skip("fullcoverage doesn't work on Python 2.")
+        # It only works with the C tracer, and if we aren't measuring ourselves.
+        if not env.C_TRACER or env.METACOV:
+            self.skip("fullcoverage only works with the C tracer.")
+
+        # fullcoverage is a trick to get stdlib modules measured from
+        # the very beginning of the process. Here we import os and
+        # then check how many lines are measured.
+        self.make_file("getenv.py", """\
+            import os
+            print("FOOEY == %s" % os.getenv("FOOEY"))
+            """)
+
+        fullcov = os.path.join(
+            os.path.dirname(coverage.__file__), "fullcoverage"
+            )
+        self.set_environ("FOOEY", "BOO")
+        self.set_environ("PYTHONPATH", fullcov)
+        out = self.run_command("python -m coverage run -L getenv.py")
+        self.assertEqual(out, "FOOEY == BOO\n")
+        data = coverage.CoverageData()
+        data.read_file(".coverage")
+        # The actual number of executed lines in os.py when it's
+        # imported is 120 or so.  Just running os.getenv executes
+        # about 5.
+        self.assertGreater(data.line_counts()['os.py'], 50)
+
+    def test_deprecation_warnings(self):
+        # Test that coverage doesn't trigger deprecation warnings.
+        # https://bitbucket.org/ned/coveragepy/issue/305/pendingdeprecationwarning-the-imp-module
+        self.make_file("allok.py", """\
+            import warnings
+            warnings.simplefilter('default')
+            import coverage
+            print("No warnings!")
+            """)
+        out = self.run_command("python allok.py")
+        self.assertEqual(out, "No warnings!\n")
+
+    def test_run_twice(self):
+        # https://bitbucket.org/ned/coveragepy/issue/353/40a3-introduces-an-unexpected-third-case
+        self.make_file("foo.py", """\
+            def foo():
+                pass
+            """)
+        self.make_file("run_twice.py", """\
+            import coverage
+
+            for _ in [1, 2]:
+                inst = coverage.Coverage(source=['foo'])
+                inst.load()
+                inst.start()
+                import foo
+                inst.stop()
+                inst.combine()
+                inst.save()
+            """)
+        out = self.run_command("python run_twice.py")
+        self.assertEqual(
+            out,
+            "Coverage.py warning: Module foo was previously imported, but not measured.\n"
+        )
+
+
+class AliasedCommandTest(CoverageTest):
+    """Tests of the version-specific command aliases."""
+
+    run_in_temp_dir = False
+
+    def test_major_version_works(self):
+        # "coverage2" works on py2
+        cmd = "coverage%d" % sys.version_info[0]
+        out = self.run_command(cmd)
+        self.assertIn("Code coverage for Python", out)
+
+    def test_wrong_alias_doesnt_work(self):
+        # "coverage3" doesn't work on py2
+        badcmd = "coverage%d" % (5 - sys.version_info[0])
+        out = self.run_command(badcmd)
+        self.assertNotIn("Code coverage for Python", out)
+
+    def test_specific_alias_works(self):
+        # "coverage-2.7" works on py2.7
+        cmd = "coverage-%d.%d" % sys.version_info[:2]
+        out = self.run_command(cmd)
+        self.assertIn("Code coverage for Python", out)
+
+
+class PydocTest(CoverageTest):
+    """Test that pydoc can get our information."""
+
+    run_in_temp_dir = False
+
+    def assert_pydoc_ok(self, name, thing):
+        """Check that pydoc of `name` finds the docstring from `thing`."""
+        # Run pydoc.
+        out = self.run_command("python -m pydoc " + name)
+        # It should say "Help on..", and not have a traceback
+        self.assert_starts_with(out, "Help on ")
+        self.assertNotIn("Traceback", out)
+
+        # All of the lines in the docstring should be there somewhere.
+        for line in thing.__doc__.splitlines():
+            self.assertIn(line.strip(), out)
+
+    def test_pydoc_coverage(self):
+        self.assert_pydoc_ok("coverage", coverage)
+
+    def test_pydoc_coverage_coverage(self):
+        self.assert_pydoc_ok("coverage.Coverage", coverage.Coverage)
+
+
+class FailUnderTest(CoverageTest):
+    """Tests of the --fail-under switch."""
+
+    def setUp(self):
+        super(FailUnderTest, self).setUp()
+        self.make_file("forty_two_plus.py", """\
+            # I have 42.857% (3/7) coverage!
+            a = 1
+            b = 2
+            if a > 3:
+                b = 4
+                c = 5
+                d = 6
+                e = 7
+            """)
+        st, _ = self.run_command_status("coverage run forty_two_plus.py")
+        self.assertEqual(st, 0)
+        st, out = self.run_command_status("coverage report")
+        self.assertEqual(st, 0)
+        self.assertEqual(
+            self.last_line_squeezed(out),
+            "forty_two_plus.py 7 4 43%"
+        )
+
+    def test_report(self):
+        st, _ = self.run_command_status("coverage report --fail-under=42")
+        self.assertEqual(st, 0)
+        st, _ = self.run_command_status("coverage report --fail-under=43")
+        self.assertEqual(st, 0)
+        st, _ = self.run_command_status("coverage report --fail-under=44")
+        self.assertEqual(st, 2)
+
+    def test_html_report(self):
+        st, _ = self.run_command_status("coverage html --fail-under=42")
+        self.assertEqual(st, 0)
+        st, _ = self.run_command_status("coverage html --fail-under=43")
+        self.assertEqual(st, 0)
+        st, _ = self.run_command_status("coverage html --fail-under=44")
+        self.assertEqual(st, 2)
+
+    def test_xml_report(self):
+        st, _ = self.run_command_status("coverage xml --fail-under=42")
+        self.assertEqual(st, 0)
+        st, _ = self.run_command_status("coverage xml --fail-under=43")
+        self.assertEqual(st, 0)
+        st, _ = self.run_command_status("coverage xml --fail-under=44")
+        self.assertEqual(st, 2)
+
+    def test_fail_under_in_config(self):
+        self.make_file(".coveragerc", "[report]\nfail_under = 43\n")
+        st, _ = self.run_command_status("coverage report")
+        self.assertEqual(st, 0)
+
+        self.make_file(".coveragerc", "[report]\nfail_under = 44\n")
+        st, _ = self.run_command_status("coverage report")
+        self.assertEqual(st, 2)
+
+
+class FailUnderNoFilesTest(CoverageTest):
+    """Test that nothing to report results in an error exit status."""
+    def setUp(self):
+        super(FailUnderNoFilesTest, self).setUp()
+        self.make_file(".coveragerc", "[report]\nfail_under = 99\n")
+
+    def test_report(self):
+        st, out = self.run_command_status("coverage report")
+        self.assertIn('No data to report.', out)
+        self.assertEqual(st, 1)
+
+    def test_xml(self):
+        st, out = self.run_command_status("coverage xml")
+        self.assertIn('No data to report.', out)
+        self.assertEqual(st, 1)
+
+    def test_html(self):
+        st, out = self.run_command_status("coverage html")
+        self.assertIn('No data to report.', out)
+        self.assertEqual(st, 1)
+
+
+class FailUnderEmptyFilesTest(CoverageTest):
+    """Test that empty files produce the proper fail_under exit status."""
+    def setUp(self):
+        super(FailUnderEmptyFilesTest, self).setUp()
+
+        self.make_file(".coveragerc", "[report]\nfail_under = 99\n")
+        self.make_file("empty.py", "")
+        st, _ = self.run_command_status("coverage run empty.py")
+        self.assertEqual(st, 0)
+
+    def test_report(self):
+        st, _ = self.run_command_status("coverage report")
+        self.assertEqual(st, 2)
+
+    def test_xml(self):
+        st, _ = self.run_command_status("coverage xml")
+        self.assertEqual(st, 2)
+
+    def test_html(self):
+        st, _ = self.run_command_status("coverage html")
+        self.assertEqual(st, 2)
+
+
+def possible_pth_dirs():
+    """Produce a sequence of directories for trying to write .pth files."""
+    # First look through sys.path, and we find a .pth file, then it's a good
+    # place to put ours.
+    for d in sys.path:
+        g = glob.glob(os.path.join(d, "*.pth"))
+        if g:
+            yield d
+
+    # If we're still looking, then try the Python library directory.
+    # https://bitbucket.org/ned/coveragepy/issue/339/pth-test-malfunctions
+    import distutils.sysconfig                  # pylint: disable=import-error
+    yield distutils.sysconfig.get_python_lib()
+
+
+class ProcessCoverageMixin(object):
+    """Set up a .pth file to coverage-measure all sub-processes."""
+
+    def setUp(self):
+        super(ProcessCoverageMixin, self).setUp()
+        # Find a place to put a .pth file.
+        pth_contents = "import coverage; coverage.process_startup()\n"
+        for pth_dir in possible_pth_dirs():             # pragma: part covered
+            pth_path = os.path.join(pth_dir, "subcover.pth")
+            with open(pth_path, "w") as pth:
+                try:
+                    pth.write(pth_contents)
+                    self.pth_path = pth_path
+                    break
+                except (IOError, OSError):              # pragma: not covered
+                    pass
+        else:                                           # pragma: not covered
+            raise Exception("Couldn't find a place for the .pth file")
+
+        self.addCleanup(os.remove, self.pth_path)
+
+
+class ProcessStartupTest(ProcessCoverageMixin, CoverageTest):
+    """Test that we can measure coverage in sub-processes."""
+
+    def test_subprocess_with_pth_files(self):           # pragma: not covered
+        if env.METACOV:
+            self.skip("Can't test sub-process pth file suppport during metacoverage")
+
+        # Main will run sub.py
+        self.make_file("main.py", """\
+            import os, os.path, sys
+            ex = os.path.basename(sys.executable)
+            os.system(ex + " sub.py")
+            """)
+        # sub.py will write a few lines.
+        self.make_file("sub.py", """\
+            with open("out.txt", "w") as f:
+                f.write("Hello, world!\\n")
+            """)
+        self.make_file("coverage.ini", """\
+            [run]
+            data_file = .mycovdata
+            """)
+        self.set_environ("COVERAGE_PROCESS_START", "coverage.ini")
+        import main             # pylint: disable=import-error,unused-variable
+
+        with open("out.txt") as f:
+            self.assertEqual(f.read(), "Hello, world!\n")
+
+        # Read the data from .coverage
+        self.assert_exists(".mycovdata")
+        data = coverage.CoverageData()
+        data.read_file(".mycovdata")
+        self.assertEqual(data.line_counts()['sub.py'], 2)
+
+
+class ProcessStartupWithSourceTest(ProcessCoverageMixin, CoverageTest):
+    """Show that we can configure {[run]source} during process-level coverage.
+
+    There are three interesting variables, for a total of eight tests:
+
+        1. -m versus a simple script argument (for example, `python myscript`),
+
+        2. filtering for the top-level (main.py) or second-level (sub.py)
+           module, and
+
+        3. whether the files are in a package or not.
+
+    """
+
+    def assert_pth_and_source_work_together(
+        self, dashm, package, source
+    ):                                                  # pragma: not covered
+        """Run the test for a particular combination of factors.
+
+        The arguments are all strings:
+
+        * `dashm`: Either "" (run the program as a file) or "-m" (run the
+          program as a module).
+
+        * `package`: Either "" (put the source at the top level) or a
+          package name to use to hold the source.
+
+        * `source`: Either "main" or "sub", which file to use as the
+          ``--source`` argument.
+
+        """
+        if env.METACOV:
+            self.skip("Can't test sub-process pth file suppport during metacoverage")
+
+        def fullname(modname):
+            """What is the full module name for `modname` for this test?"""
+            if package and dashm:
+                return '.'.join((package, modname))
+            else:
+                return modname
+
+        def path(basename):
+            """Where should `basename` be created for this test?"""
+            return os.path.join(package, basename)
+
+        # Main will run sub.py.
+        self.make_file(path("main.py"), """\
+            import %s
+            if True: pass
+            """ % fullname('sub'))
+        if package:
+            self.make_file(path("__init__.py"), "")
+        # sub.py will write a few lines.
+        self.make_file(path("sub.py"), """\
+            with open("out.txt", "w") as f:
+                f.write("Hello, world!")
+            """)
+        self.make_file("coverage.ini", """\
+            [run]
+            source = %s
+            """ % fullname(source))
+
+        self.set_environ("COVERAGE_PROCESS_START", "coverage.ini")
+
+        if dashm:
+            cmd = "python -m %s" % fullname('main')
+        else:
+            cmd = "python %s" % path('main.py')
+
+        self.run_command(cmd)
+
+        with open("out.txt") as f:
+            self.assertEqual(f.read(), "Hello, world!")
+
+        # Read the data from .coverage
+        self.assert_exists(".coverage")
+        data = coverage.CoverageData()
+        data.read_file(".coverage")
+        summary = data.line_counts()
+        print(summary)
+        self.assertEqual(summary[source + '.py'], 2)
+        self.assertEqual(len(summary), 1)
+
+    def test_dashm_main(self):
+        self.assert_pth_and_source_work_together('-m', '', 'main')
+
+    def test_script_main(self):
+        self.assert_pth_and_source_work_together('', '', 'main')
+
+    def test_dashm_sub(self):
+        self.assert_pth_and_source_work_together('-m', '', 'sub')
+
+    def test_script_sub(self):
+        self.assert_pth_and_source_work_together('', '', 'sub')
+
+    def test_dashm_pkg_main(self):
+        self.assert_pth_and_source_work_together('-m', 'pkg', 'main')
+
+    def test_script_pkg_main(self):
+        self.assert_pth_and_source_work_together('', 'pkg', 'main')
+
+    def test_dashm_pkg_sub(self):
+        self.assert_pth_and_source_work_together('-m', 'pkg', 'sub')
+
+    def test_script_pkg_sub(self):
+        self.assert_pth_and_source_work_together('', 'pkg', 'sub')
+
+
+def remove_matching_lines(text, pat):
+    """Return `text` with all lines matching `pat` removed."""
+    lines = [l for l in text.splitlines(True) if not re.search(pat, l)]
+    return "".join(lines)