Promote re_line and re_lines to real helpers, with tests.

4 files changed, 72 insertions, 31 deletions

diff --git a/tests/helpers.py b/tests/helpers.py
index a132872..344ed71 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -4,6 +4,7 @@
 """Helpers for coverage.py tests."""
 
 import os
+import re
 import subprocess
 import sys
 
@@ -77,3 +78,26 @@ class CheckUniqueFilenames(object):
         self.filenames.add(filename)
         ret = self.wrapped(filename, *args, **kwargs)
         return ret
+
+
+def re_lines(text, pat, match=True):
+    """Return the text of lines that match `pat` in the string `text`.
+
+    If `match` is false, the selection is inverted: only the non-matching
+    lines are included.
+
+    Returns a string, the text of only the selected lines.
+
+    """
+    return "".join(l for l in text.splitlines(True) if bool(re.search(pat, l)) == match)
+
+
+def re_line(text, pat):
+    """Return the one line in `text` that matches regex `pat`.
+
+    Raises an AssertionError if more than one, or less than one, line matches.
+
+    """
+    lines = re_lines(text, pat).splitlines()
+    assert len(lines) == 1
+    return lines[0]
diff --git a/tests/test_process.py b/tests/test_process.py
index d77dfda..6ed566e 100644
--- a/tests/test_process.py
+++ b/tests/test_process.py
@@ -18,6 +18,7 @@ from coverage import env, CoverageData
 from coverage.misc import output_encoding
 
 from tests.coveragetest import CoverageTest
+from tests.helpers import re_lines
 
 
 class ProcessTest(CoverageTest):
@@ -388,8 +389,7 @@ class ProcessTest(CoverageTest):
         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)
+            out2 = re_lines(out2, "toplevel", match=False)
         self.assertMultiLineEqual(out, out2)
 
         # But also make sure that the output is what we expect.
@@ -722,8 +722,8 @@ class EnvironmentTest(CoverageTest):
         # 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)
+        out_cov = re_lines(out_cov, ignored, match=False)
+        out_py = re_lines(out_py, ignored, match=False)
         self.assertMultiLineEqual(out_cov, out_py)
         self.assert_execfile_output(out_cov)
 
@@ -1405,9 +1405,3 @@ class ProcessStartupWithSourceTest(ProcessCoverageMixin, CoverageTest):
 
     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)
diff --git a/tests/test_testing.py b/tests/test_testing.py
index b74d08f..a7f60b3 100644
--- a/tests/test_testing.py
+++ b/tests/test_testing.py
@@ -8,12 +8,14 @@ import datetime
 import os
 import sys
 
+import pytest
+
 import coverage
 from coverage.backunittest import TestCase
 from coverage.files import actual_path
 
 from tests.coveragetest import CoverageTest
-from tests.helpers import CheckUniqueFilenames
+from tests.helpers import CheckUniqueFilenames, re_lines, re_line
 
 
 class TestingTest(TestCase):
@@ -131,12 +133,14 @@ class CoverageTestTest(CoverageTest):
         self.assertEqual(out[2], 'XYZZY')
 
         # Try it with a "coverage debug sys" command.
-        out = self.run_command("coverage debug sys").splitlines()
-        # "environment: COV_FOOBAR = XYZZY" or "COV_FOOBAR = XYZZY"
-        executable = next(l for l in out if "executable:" in l)     # pragma: part covered
+        out = self.run_command("coverage debug sys")
+
+        executable = re_line(out, "executable:")
         executable = executable.split(":", 1)[1].strip()
-        self.assertTrue(same_python_executable(executable, sys.executable))
-        environ = next(l for l in out if "COV_FOOBAR" in l)         # pragma: part covered
+        self.assertTrue(_same_python_executable(executable, sys.executable))
+
+        # "environment: COV_FOOBAR = XYZZY" or "COV_FOOBAR = XYZZY"
+        environ = re_line(out, "COV_FOOBAR")
         _, _, environ = environ.rpartition(":")
         self.assertEqual(environ.strip(), "COV_FOOBAR = XYZZY")
 
@@ -168,7 +172,38 @@ class CheckUniqueFilenamesTest(CoverageTest):
             stub.method("file1")
 
 
-def same_python_executable(e1, e2):
+@pytest.mark.parametrize("text, pat, result", [
+    ("line1\nline2\nline3\n", "line", "line1\nline2\nline3\n"),
+    ("line1\nline2\nline3\n", "[13]", "line1\nline3\n"),
+    ("line1\nline2\nline3\n", "X", ""),
+])
+def test_re_lines(text, pat, result):
+    assert re_lines(text, pat) == result
+
+@pytest.mark.parametrize("text, pat, result", [
+    ("line1\nline2\nline3\n", "line", ""),
+    ("line1\nline2\nline3\n", "[13]", "line2\n"),
+    ("line1\nline2\nline3\n", "X", "line1\nline2\nline3\n"),
+])
+def test_re_lines_inverted(text, pat, result):
+    assert re_lines(text, pat, match=False) == result
+
+@pytest.mark.parametrize("text, pat, result", [
+    ("line1\nline2\nline3\n", "2", "line2"),
+])
+def test_re_line(text, pat, result):
+    assert re_line(text, pat) == result
+
+@pytest.mark.parametrize("text, pat", [
+    ("line1\nline2\nline3\n", "line"),      # too many matches
+    ("line1\nline2\nline3\n", "X"),         # no matches
+])
+def test_re_line_bad(text, pat):
+    with pytest.raises(AssertionError):
+        re_line(text, pat)
+
+
+def _same_python_executable(e1, e2):
     """Determine if `e1` and `e2` refer to the same Python executable.
 
     Either path could include symbolic links.  The two paths might not refer
diff --git a/tests/test_xml.py b/tests/test_xml.py
index dd14b92..9f1781a 100644
--- a/tests/test_xml.py
+++ b/tests/test_xml.py
@@ -13,6 +13,7 @@ from coverage.files import abs_file
 from tests.coveragetest import CoverageTest
 from tests.goldtest import CoverageGoldTest
 from tests.goldtest import change_dir, compare
+from tests.helpers import re_line, re_lines
 
 
 class XmlTestHelpers(CoverageTest):
@@ -194,7 +195,7 @@ class XmlPackageStructureTest(XmlTestHelpers, CoverageTest):
         cov.xml_report(outfile="-")
         packages_and_classes = re_lines(self.stdout(), r"<package |<class ")
         scrubs = r' branch-rate="0"| complexity="0"| line-rate="[\d.]+"'
-        return clean("".join(packages_and_classes), scrubs)
+        return clean(packages_and_classes, scrubs)
 
     def assert_package_and_class_tags(self, cov, result):
         """Check the XML package and class tags from `cov` match `result`."""
@@ -282,19 +283,6 @@ class XmlPackageStructureTest(XmlTestHelpers, CoverageTest):
             """)
 
 
-def re_lines(text, pat):
-    """Return a list of lines that match `pat` in the string `text`."""
-    lines = [l for l in text.splitlines(True) if re.search(pat, l)]
-    return lines
-
-
-def re_line(text, pat):
-    """Return the one line in `text` that matches regex `pat`."""
-    lines = re_lines(text, pat)
-    assert len(lines) == 1
-    return lines[0]
-
-
 def clean(text, scrub=None):
     """Clean text to prepare it for comparison.