Implement file globbing and test matching within watch mode

Make watch mode interactive by allowing users to specify an additional glob pattern to select specific files, and a `--match` pattern to select specific tests. This means you no longer have to exit watch mode to achieve the same.

Co-authored-by: Michael Mulet <mike@lfds.io>
Co-authored-by: Mark Wubben <mark@novemberborn.net>

Author: mmulet

docs/recipes/watch-mode.md

@@ -34,6 +34,34 @@ export default {
 
 If your tests write to disk they may trigger the watcher to rerun your tests. Configuring additional ignore patterns helps avoid this.
 
+### Filter tests while watching
+
+You may also filter tests while watching by using the CLI. For example, after running
+
+```console
+npx ava --watch
+```
+
+You will see a prompt like this:
+
+```console
+ Type `g` followed by enter to filter test files by a glob pattern
+ Type `m` followed by enter to filter tests by their title
+ Type `r` followed by enter to rerun tests
+ Type `u` followed by enter to update snapshots in selected tests
+> 
+```
+
+So, to run only tests numbered like
+
+- foo23434
+- foo4343
+- foo93823
+
+You can type `m` and press enter, then type `foo*` and press enter. This will then run all tests that match that glob.
+
+Afterwards you can use the `r` command to run the matched tests again, or `a` command to run **all** tests.
+
 ## Dependency tracking
 
 AVA tracks which source files your test files depend on. If you change such a dependency only the test file that depends on it will be rerun. AVA will rerun all tests if it cannot determine which test file depends on the changed source file.
@@ -62,7 +90,6 @@ Sometimes watch mode does something surprising like rerunning all tests when you
 $ DEBUG=ava:watcher npx ava --watch
 ```
 
-[`chokidar`]: https://github.com/paulmillr/chokidar
 [Install Troubleshooting]: https://github.com/paulmillr/chokidar#install-troubleshooting
 [`ignore-by-default`]: https://github.com/novemberborn/ignore-by-default
 [`.only` modifier]: ../01-writing-tests.md#running-specific-tests

lib/api.js

@@ -88,7 +88,7 @@ export default class Api extends Emittery {
 		}
 	}
 
-	async run({files: selectedFiles = [], filter = [], runtimeOptions = {}} = {}) { // eslint-disable-line complexity
+	async run({files: selectedFiles = [], filter = [], runtimeOptions = {}, testFileSelector} = {}) { // eslint-disable-line complexity
 		let setupOrGlobError;
 
 		const apiOptions = this.options;
@@ -149,7 +149,9 @@ export default class Api extends Emittery {
 		let testFiles;
 		try {
 			testFiles = await globs.findTests({cwd: this.options.projectDir, ...apiOptions.globs});
-			if (selectedFiles.length === 0) {
+			if (typeof testFileSelector === 'function') {
+				selectedFiles = testFileSelector(testFiles, selectedFiles);
+			} else if (selectedFiles.length === 0) {
 				selectedFiles = filter.length === 0 ? testFiles : globs.applyTestFileFilter({
 					cwd: this.options.projectDir,
 					filter: filter.map(({pattern}) => pattern),
@@ -163,7 +165,7 @@ export default class Api extends Emittery {
 		}
 
 		const selectionInsights = {
-			filter,
+			filter: selectedFiles.appliedFilters ?? filter,
 			ignoredFilterPatternFiles: selectedFiles.ignoredFilterPatternFiles ?? [],
 			testFileCount: testFiles.length,
 			selectionCount: selectedFiles.length,
@@ -201,8 +203,8 @@ export default class Api extends Emittery {
 				failFastEnabled: failFast,
 				filePathPrefix: getFilePathPrefix(selectedFiles),
 				files: selectedFiles,
-				matching: apiOptions.match.length > 0,
-				previousFailures: runtimeOptions.previousFailures ?? 0,
+				matching: apiOptions.match.length > 0 || runtimeOptions.interactiveMatchPattern !== undefined,
+				previousFailures: runtimeOptions.countPreviousFailures?.() ?? 0,
 				firstRun: runtimeOptions.firstRun ?? true,
 				status: runStatus,
 			});
@@ -265,12 +267,13 @@ export default class Api extends Emittery {
 
 				const lineNumbers = getApplicableLineNumbers(globs.normalizeFileForMatching(apiOptions.projectDir, file), filter);
 				// Removing `providers` and `sortTestFiles` fields because they cannot be transferred to the worker threads.
-				const {providers, sortTestFiles, ...forkOptions} = apiOptions;
+				const {providers, sortTestFiles, match, ...forkOptions} = apiOptions;
 				const options = {
 					...forkOptions,
 					providerStates,
 					lineNumbers,
 					recordNewSnapshots: !isCi,
+					match: runtimeOptions.interactiveMatchPattern === undefined ? match : [...match, runtimeOptions.interactiveMatchPattern],
 				};
 
 				if (runtimeOptions.updateSnapshots) {

lib/reporters/default.js

@@ -26,24 +26,29 @@ class LineWriter extends stream.Writable {
 
 		this.dest = dest;
 		this.columns = dest.columns ?? 80;
-		this.lastLineIsEmpty = false;
+		this.lastLineIsEmpty = true;
 	}
 
 	_write(chunk, _, callback) {
 		this.dest.write(chunk);
 		callback();
 	}
 
-	writeLine(string) {
+	writeLine(string, indent = true) {
 		if (string) {
-			this.write(indentString(string, 2) + os.EOL);
+			this.write((indent ? indentString(string, 2) : string) + os.EOL);
 			this.lastLineIsEmpty = false;
 		} else {
 			this.write(os.EOL);
 			this.lastLineIsEmpty = true;
 		}
 	}
 
+	write(string) {
+		this.lastLineIsEmpty = false;
+		super.write(string);
+	}
+
 	ensureEmptyLine() {
 		if (!this.lastLineIsEmpty) {
 			this.writeLine();
@@ -120,7 +125,6 @@ export default class Reporter {
 		this.previousFailures = 0;
 
 		this.failFastEnabled = false;
-		this.lastLineIsEmpty = false;
 		this.matching = false;
 
 		this.removePreviousListener = null;
@@ -628,7 +632,7 @@ export default class Reporter {
 				this.lineWriter.writeLine(colors.error(`${figures.cross} Couldn’t find any files to test` + firstLinePostfix));
 			} else {
 				const {testFileCount: count} = this.selectionInsights;
-				this.lineWriter.writeLine(colors.error(`${figures.cross} Based on your configuration, ${count} test ${plur('file was', 'files were', count)} found, but did not match the CLI arguments:` + firstLinePostfix));
+				this.lineWriter.writeLine(colors.error(`${figures.cross} Based on your configuration, ${count} test ${plur('file was', 'files were', count)} found, but did not match the filters:` + firstLinePostfix));
 				this.lineWriter.writeLine();
 				for (const {pattern} of this.selectionInsights.filter) {
 					this.lineWriter.writeLine(colors.error(`* ${pattern}`));