Add shellcheck violation tool in diff-quality

diff_cover/diff_quality_tool.py

@@ -54,6 +54,7 @@
     pycodestyle_driver,
     pydocstyle_driver,
     pyflakes_driver,
+    shellcheck_driver,
 )
 
 QUALITY_DRIVERS = {
@@ -69,6 +70,7 @@
     "checkstylexml": CheckstyleXmlDriver(),
     "findbugs": FindbugsXmlDriver(),
     "pmd": PmdXmlDriver(),
+    "shellcheck": shellcheck_driver,
 }
 
 VIOLATION_CMD_HELP = "Which code quality tool to use (%s)" % "/".join(

diff_cover/violationsreporters/violations_reporter.py

@@ -474,6 +474,18 @@ def measured_lines(self, src_path):
     command_to_check_install=["jshint", "-v"],
 )
 
+shellcheck_driver = RegexBasedDriver(
+    name="shellcheck",
+    supported_extensions=["sh"],
+    # Use gcc format to ease violations parsing
+    command=["shellcheck", "-f", "gcc"],
+    expression=r"^([^:]+):(\d+):(\d+: .*)$",
+    command_to_check_install=["shellcheck", "-V"],
+    # shellcheck exit code is 1 if there are violations
+    # https://www.shellcheck.net/wiki/Integration#exit-codes
+    exit_codes=[0, 1],
+)
+
 
 class EslintDriver(RegexBasedDriver):
     def __init__(self):

tests/test_violations_reporter.py

@@ -33,6 +33,7 @@
     pycodestyle_driver,
     pydocstyle_driver,
     pyflakes_driver,
+    shellcheck_driver,
 )
 
 
@@ -1712,6 +1713,70 @@ def test_report_root_path(self):
         assert actual_violations == [expected_violation]
 
 
+class TestShellCheckQualityReporterTest:
+    """Tests for shellcheck quality violations."""
+
+    def test_no_such_file(self):
+        """Expect that we get no results."""
+        quality = QualityReporter(shellcheck_driver)
+
+        result = quality.violations("")
+        assert result == []
+
+    def test_no_shell_file(self):
+        """Expect that we get no results because no shell files."""
+        quality = QualityReporter(shellcheck_driver)
+        file_paths = ["file1.coffee", "subdir/file2.hs"]
+        for path in file_paths:
+            result = quality.violations(path)
+            assert result == []
+
+    def test_quality(self, process_patcher):
+        """Integration test."""
+        process_patcher(
+            (
+                dedent(
+                    """
+            foo/bar/path/to/file.sh:2:18: note: Double quote to prevent globbing and word splitting. [SC2086]
+            foo/bar/path/to/file.sh:53:10: warning: Use 'cd ... || exit' or 'cd ... || return' in case cd fails. [SC2164]
+            """
+                )
+                .strip()
+                .encode("ascii"),
+                "",
+            )
+        )
+
+        expected_violations = [
+            Violation(
+                2,
+                "18: note: Double quote to prevent globbing and word splitting. [SC2086]",
+            ),
+            Violation(
+                53,
+                "10: warning: Use 'cd ... || exit' or 'cd ... || return' in case cd fails. [SC2164]",
+            ),
+        ]
+
+        # Parse the report
+        quality = QualityReporter(shellcheck_driver)
+
+        # Expect that the name is set
+        assert quality.name() == "shellcheck"
+
+        # Measured_lines is undefined for a
+        # quality reporter since all lines are measured
+        assert quality.measured_lines("foo/bar/path/to/file.sh") is None
+
+        # Expect that we get violations for file1.py only
+        # We're not guaranteed that the violations are returned
+        # in any particular order.
+        actual_violations = quality.violations("foo/bar/path/to/file.sh")
+        assert len(actual_violations) == len(expected_violations)
+        for expected in expected_violations:
+            assert expected in actual_violations
+
+
 class TestSimpleCommandTestCase:
     """
     Tests that the exit code detected by the method is passed as the return value of the method.