refactor(test): re_lines is more useful if it returns a list

4 files changed, 28 insertions, 19 deletions

diff --git a/tests/helpers.py b/tests/helpers.py
index 185f20dd..7e6594ac 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -134,15 +134,21 @@ class CheckUniqueFilenames:
 
 
 def re_lines(text, pat, match=True):
-    """Return the text of lines that match `pat` in the string `text`.
+    """Return a list of lines selected by `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.
+    Returns a list, the selected lines, without line endings.
 
     """
-    return "".join(l for l in text.splitlines(True) if bool(re.search(pat, l)) == match)
+    assert len(pat) < 200, "It's super-easy to swap the arguments to re_lines"
+    return [l for l in text.splitlines() if bool(re.search(pat, l)) == match]
+
+
+def re_lines_text(text, pat, match=True):
+    """Return the multi-line text of lines selected by `pat`."""
+    return "".join(l + "\n" for l in re_lines(text, pat, match=match))
 
 
 def re_line(text, pat):
@@ -151,7 +157,7 @@ def re_line(text, pat):
     Raises an AssertionError if more than one, or less than one, line matches.
 
     """
-    lines = re_lines(text, pat).splitlines()
+    lines = re_lines(text, pat)
     assert len(lines) == 1
     return lines[0]
 
diff --git a/tests/test_debug.py b/tests/test_debug.py
index 740bd617..564c2c29 100644
--- a/tests/test_debug.py
+++ b/tests/test_debug.py
@@ -15,7 +15,7 @@ from coverage.debug import filter_text, info_formatter, info_header, short_id, s
 from coverage.debug import clipped_repr
 
 from tests.coveragetest import CoverageTest
-from tests.helpers import re_line, re_lines
+from tests.helpers import re_line, re_lines, re_lines_text
 
 
 class InfoFormatterTest(CoverageTest):
@@ -141,7 +141,7 @@ class DebugTraceTest(CoverageTest):
 
         # Now our lines are always prefixed with the process id.
         pid_prefix = r"^%5d\.[0-9a-f]{4}: " % os.getpid()
-        pid_lines = re_lines(out_lines, pid_prefix)
+        pid_lines = re_lines_text(out_lines, pid_prefix)
         assert pid_lines == out_lines
 
         # We still have some tracing, and some not tracing.
@@ -152,9 +152,9 @@ class DebugTraceTest(CoverageTest):
         out_lines = self.f1_debug_output(["pid", "dataop", "dataio", "callers"])
         # For every real message, there should be a stack trace with a line like
         #       "f1_debug_output : /Users/ned/coverage/tests/test_debug.py @71"
-        real_messages = re_lines(out_lines, r":\d+", match=False).splitlines()
+        real_messages = re_lines(out_lines, r":\d+", match=False)
         frame_pattern = r"\s+f1_debug_output : .*tests[/\\]test_debug.py:\d+$"
-        frames = re_lines(out_lines, frame_pattern).splitlines()
+        frames = re_lines(out_lines, frame_pattern)
         assert len(real_messages) == len(frames)
 
         last_line = out_lines.splitlines()[-1]
@@ -178,7 +178,7 @@ class DebugTraceTest(CoverageTest):
         for label in labels:
             label_pat = r"^\s*%s: " % label
             msg = "Incorrect lines for %r" % label
-            assert 1 == len(re_lines(out_lines, label_pat).splitlines()), msg
+            assert 1 == len(re_lines(out_lines, label_pat)), msg
 
     def test_debug_sys(self):
         out_lines = self.f1_debug_output(["sys"])
@@ -192,7 +192,7 @@ class DebugTraceTest(CoverageTest):
         for label in labels:
             label_pat = r"^\s*%s: " % label
             msg = "Incorrect lines for %r" % label
-            assert 1 == len(re_lines(out_lines, label_pat).splitlines()), msg
+            assert 1 == len(re_lines(out_lines, label_pat)), msg
 
     def test_debug_sys_ctracer(self):
         out_lines = self.f1_debug_output(["sys"])
diff --git a/tests/test_process.py b/tests/test_process.py
index 65a6e75d..f5ffee51 100644
--- a/tests/test_process.py
+++ b/tests/test_process.py
@@ -23,7 +23,8 @@ from coverage.data import line_counts
 from coverage.files import abs_file, python_reported_file
 
 from tests.coveragetest import CoverageTest, TESTS_DIR
-from tests.helpers import change_dir, make_file, nice_file, os_sep, re_lines, run_command
+from tests.helpers import change_dir, make_file, nice_file, os_sep
+from tests.helpers import re_lines, re_lines_text, run_command
 
 
 class ProcessTest(CoverageTest):
@@ -500,7 +501,7 @@ class ProcessTest(CoverageTest):
         out2 = self.run_command("python throw.py")
         if env.PYPY:
             # Pypy has an extra frame in the traceback for some reason
-            out2 = re_lines(out2, "toplevel", match=False)
+            out2 = re_lines_text(out2, "toplevel", match=False)
         assert out == out2
 
         # But also make sure that the output is what we expect.
@@ -869,8 +870,8 @@ class EnvironmentTest(CoverageTest):
 
         if env.JYTHON:                  # pragma: only jython
             # Argv0 is different for Jython, remove that from the comparison.
-            expected = re_lines(expected, r'\s+"argv0":', match=False)
-            actual = re_lines(actual, r'\s+"argv0":', match=False)
+            expected = re_lines_text(expected, r'\s+"argv0":', match=False)
+            actual = re_lines_text(actual, r'\s+"argv0":', match=False)
 
         assert actual == expected
 
@@ -906,8 +907,8 @@ class EnvironmentTest(CoverageTest):
         # the comparison also...
         if env.PYPY:
             ignored = re.escape(os.getcwd())
-            expected = re_lines(expected, ignored, match=False)
-            actual = re_lines(actual, ignored, match=False)
+            expected = re_lines_text(expected, ignored, match=False)
+            actual = re_lines_text(actual, ignored, match=False)
         self.assert_tryexecfile_output(expected, actual)
 
     def test_coverage_run_dashm_dir_no_init_is_like_python(self):
diff --git a/tests/test_testing.py b/tests/test_testing.py
index 37130074..8d559fe4 100644
--- a/tests/test_testing.py
+++ b/tests/test_testing.py
@@ -19,7 +19,7 @@ from coverage.files import actual_path
 from tests.coveragetest import CoverageTest
 from tests.helpers import (
     arcs_to_arcz_repr, arcz_to_arcs, assert_count_equal, assert_coverage_warnings,
-    CheckUniqueFilenames, re_lines, re_line, without_module,
+    CheckUniqueFilenames, re_lines, re_lines_text, re_line, without_module,
 )
 
 
@@ -302,7 +302,8 @@ class ReLinesTest(CoverageTest):
         ("line1\nline2\nline3\n", "X", ""),
     ])
     def test_re_lines(self, text, pat, result):
-        assert re_lines(text, pat) == result
+        assert re_lines_text(text, pat) == result
+        assert re_lines(text, pat) == result.splitlines()
 
     @pytest.mark.parametrize("text, pat, result", [
         ("line1\nline2\nline3\n", "line", ""),
@@ -310,7 +311,8 @@ class ReLinesTest(CoverageTest):
         ("line1\nline2\nline3\n", "X", "line1\nline2\nline3\n"),
     ])
     def test_re_lines_inverted(self, text, pat, result):
-        assert re_lines(text, pat, match=False) == result
+        assert re_lines_text(text, pat, match=False) == result
+        assert re_lines(text, pat, match=False) == result.splitlines()
 
     @pytest.mark.parametrize("text, pat, result", [
         ("line1\nline2\nline3\n", "2", "line2"),