test: add more tests for ignoring files and directories (#18068)

* test: add more tests for ignoring files and directories

* add one more test

(cherry picked from commit 8c1b8dd)

Co-authored-by: Milos Djermanovic <milos.djermanovic@gmail.com>

tests/fixtures/ignores-directory-deep/tests/format/foo.js

@@ -0,0 +1 @@
+// empty

tests/fixtures/ignores-directory-deep/tests/format/jsfmt.spec.js

@@ -0,0 +1 @@
+// empty

tests/fixtures/ignores-directory-deep/tests/format/subdir/foo.js

@@ -0,0 +1 @@
+// empty

tests/fixtures/ignores-directory-deep/tests/format/subdir/jsfmt.spec.js

@@ -0,0 +1 @@
+// empty

tests/lib/eslint/flat-eslint.js

@@ -1790,6 +1790,120 @@ describe("FlatESLint", () => {
                 assert.strictEqual(results[0].filePath, getFixturePath("ignores-directory/subdir/subsubdir/a.js"));
             });
 
+            // https://github.com/eslint/eslint/issues/17964#issuecomment-1879840650
+            it("should allow directories to be unignored without also unignoring all files in them", async () => {
+                eslint = new FlatESLint({
+                    cwd: getFixturePath("ignores-directory-deep"),
+                    overrideConfigFile: true,
+                    overrideConfig: {
+                        ignores: [
+
+                            // ignore all files and directories
+                            "tests/format/**/*",
+
+                            // unignore all directories
+                            "!tests/format/**/*/",
+
+                            // unignore only specific files
+                            "!tests/format/**/jsfmt.spec.js"
+                        ]
+                    }
+                });
+                const results = await eslint.lintFiles(["."]);
+
+                assert.strictEqual(results.length, 2);
+                assert.strictEqual(results[0].errorCount, 0);
+                assert.strictEqual(results[0].warningCount, 0);
+                assert.strictEqual(results[0].filePath, getFixturePath("ignores-directory-deep/tests/format/jsfmt.spec.js"));
+                assert.strictEqual(results[1].errorCount, 0);
+                assert.strictEqual(results[1].warningCount, 0);
+                assert.strictEqual(results[1].filePath, getFixturePath("ignores-directory-deep/tests/format/subdir/jsfmt.spec.js"));
+            });
+
+            it("should allow only subdirectories to be ignored by a pattern ending with '/'", async () => {
+                eslint = new FlatESLint({
+                    cwd: getFixturePath("ignores-directory-deep"),
+                    overrideConfigFile: true,
+                    overrideConfig: {
+                        ignores: [
+                            "tests/format/*/"
+                        ]
+                    }
+                });
+                const results = await eslint.lintFiles(["."]);
+
+                assert.strictEqual(results.length, 2);
+                assert.strictEqual(results[0].errorCount, 0);
+                assert.strictEqual(results[0].warningCount, 0);
+                assert.strictEqual(results[0].filePath, getFixturePath("ignores-directory-deep/tests/format/foo.js"));
+                assert.strictEqual(results[1].errorCount, 0);
+                assert.strictEqual(results[1].warningCount, 0);
+                assert.strictEqual(results[1].filePath, getFixturePath("ignores-directory-deep/tests/format/jsfmt.spec.js"));
+            });
+
+            it("should allow only contents of a directory but not the directory itself to be ignored by a pattern ending with '**/*'", async () => {
+                eslint = new FlatESLint({
+                    cwd: getFixturePath("ignores-directory-deep"),
+                    overrideConfigFile: true,
+                    overrideConfig: {
+                        ignores: [
+                            "tests/format/**/*",
+                            "!tests/format/jsfmt.spec.js"
+                        ]
+                    }
+                });
+                const results = await eslint.lintFiles(["."]);
+
+                assert.strictEqual(results.length, 1);
+                assert.strictEqual(results[0].errorCount, 0);
+                assert.strictEqual(results[0].warningCount, 0);
+                assert.strictEqual(results[0].filePath, getFixturePath("ignores-directory-deep/tests/format/jsfmt.spec.js"));
+            });
+
+            it("should skip ignored files in an unignored directory", async () => {
+                eslint = new FlatESLint({
+                    cwd: getFixturePath("ignores-directory-deep"),
+                    overrideConfigFile: true,
+                    overrideConfig: {
+                        ignores: [
+
+                            // ignore 'tests/format/' and all its contents
+                            "tests/format/**",
+
+                            // unignore 'tests/format/', but its contents is still ignored
+                            "!tests/format/"
+                        ]
+                    }
+                });
+
+                await assert.rejects(async () => {
+                    await eslint.lintFiles(["."]);
+                }, /All files matched by '.' are ignored/u);
+            });
+
+            it("should skip files in an ignored directory even if they are matched by a negated pattern", async () => {
+                eslint = new FlatESLint({
+                    cwd: getFixturePath("ignores-directory-deep"),
+                    overrideConfigFile: true,
+                    overrideConfig: {
+                        ignores: [
+
+                            // ignore 'tests/format/' and all its contents
+                            "tests/format/**",
+
+                            // this patterns match some or all of its contents, but 'tests/format/' is still ignored
+                            "!tests/format/jsfmt.spec.js",
+                            "!tests/format/**/jsfmt.spec.js",
+                            "!tests/format/*",
+                            "!tests/format/**/*"
+                        ]
+                    }
+                });
+
+                await assert.rejects(async () => {
+                    await eslint.lintFiles(["."]);
+                }, /All files matched by '.' are ignored/u);
+            });
 
         });