Fix log error parsing bug introduced in c830eda0e (#5387)

- '\b' in regular expression needs to be in a raw string (r'\b')
- Regression test that would've caught this was unintentionally disabled

- This fixes the string and the test

lib/spack/spack/test/cmd/install.py

@@ -114,8 +114,8 @@ def test_package_output(tmpdir, capsys, install_mockery, mock_fetch):
     assert "'install'\nAFTER INSTALL" in out
 
 
-def _test_install_output_on_build_error(builtin_mock, mock_archive, mock_fetch,
-                                        config, install_mockery, capfd):
+def test_install_output_on_build_error(builtin_mock, mock_archive, mock_fetch,
+                                       config, install_mockery, capfd):
     # capfd interferes with Spack's capturing
     with capfd.disabled():
         out = install('build-error', fail_on_error=False)

lib/spack/spack/util/log_parse.py

@@ -86,7 +86,7 @@ def parse_log_events(logfile, context=6):
 
     log_events = []
     for i, line in enumerate(lines):
-        if re.search('\berror:', line, re.IGNORECASE):
+        if re.search(r'\berror:', line, re.IGNORECASE):
             event = LogEvent(
                 line.strip(),
                 i + 1,