misc: update stylelint rule tester

jest/stylelint-rule-test.js

@@ -0,0 +1,120 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// eslint-disable-next-line import/no-extraneous-dependencies
+const stylelint = require('stylelint');
+
+function getOutputCss(output) {
+  const result = output.results[0]._postcssResult;
+  return result.root.toString(result.opts.syntax);
+}
+
+global.testStylelintRule = (config, tests) => {
+  describe(tests.ruleName, () => {
+    const checkTestCaseContent = testCase =>
+      testCase.description || testCase.code || 'no description';
+
+    if (tests.accept && tests.accept.length) {
+      describe('accept cases', () => {
+        tests.accept.forEach(testCase => {
+          const spec = testCase.only ? it.only : it;
+
+          spec(checkTestCaseContent(testCase), () => {
+            const options = {
+              code: testCase.code,
+              config,
+              syntax: tests.syntax,
+            };
+
+            return stylelint.lint(options).then(output => {
+              expect(output.results[0].warnings).toEqual([]);
+
+              if (!tests.fix) {
+                return null;
+              }
+
+              // Check the fix.
+              return stylelint
+                .lint({...options, fix: true})
+                .then(fixedOutput => getOutputCss(fixedOutput))
+                .then(fixedCode => expect(fixedCode).toBe(testCase.fixed));
+            });
+          });
+        });
+      });
+    }
+
+    if (tests.reject && tests.reject.length) {
+      describe('reject cases', () => {
+        tests.reject.forEach(testCase => {
+          const skip = testCase.skip ? it.skip : it;
+          const spec = testCase.only ? it.only : skip;
+
+          spec(checkTestCaseContent(testCase), () => {
+            const options = {
+              code: testCase.code,
+              config,
+              syntax: tests.syntax,
+            };
+
+            return stylelint.lint(options).then(output => {
+              const {warnings} = output.results[0];
+              const warning = warnings[0];
+
+              expect(warnings.length).toBeGreaterThanOrEqual(1);
+              expect(testCase).toHaveMessage();
+
+              if (testCase.message != null) {
+                expect(warning.text).toBe(testCase.message);
+              }
+
+              if (testCase.line != null) {
+                expect(warning.line).toBe(testCase.line);
+              }
+
+              if (testCase.column != null) {
+                expect(warning.column).toBe(testCase.column);
+              }
+
+              if (!tests.fix) {
+                return null;
+              }
+
+              if (!testCase.fixed) {
+                throw new Error(
+                  'If using { fix: true } in test tests, all reject cases must have { fixed: .. }',
+                );
+              }
+
+              // Check the fix.
+              return stylelint
+                .lint({...options, fix: true})
+                .then(fixedOutput => getOutputCss(fixedOutput))
+                .then(fixedCode => expect(fixedCode).toBe(testCase.fixed));
+            });
+          });
+        });
+      });
+    }
+
+    expect.extend({
+      toHaveMessage(testCase) {
+        if (testCase.message == null) {
+          return {
+            message: () =>
+              'Expected "reject" test case to have a "message" property',
+            pass: false,
+          };
+        }
+
+        return {
+          pass: true,
+        };
+      },
+    });
+  });
+};