Chore: refactor so adding transforms is easier (fixes eslint#9)

To add a new transform:

1. Create a directory under tests/fixtures/transforms
2. Add the test fixtures (*.input.js, *.output.js, and *.md)
3. Implement the transform in lib/transforms

There's no need to create new (Mocha) test file. At this point, documenting the transform is still manual, but it could be easily automated.

bin/eslint-transforms.js

@@ -39,6 +39,6 @@ function execWithNodeModules(cmd) {
 execWithNodeModules([
  "jscodeshift",
  "-t",
- path.resolve(__dirname, "../lib/" + transform + "/" + transform + ".js"),
+ path.resolve(__dirname, "../lib/transforms/" + transform + ".js"),
  args.join(" ")
 ].join(" "));

tests/fixtures/transforms/new-rule-format/already-transformed.input.md

@@ -0,0 +1 @@
+tests that the transform doesn't fail if the rule was already in the new format

tests/fixtures/transforms/new-rule-format/arrow-function.md

@@ -0,0 +1 @@
+tests that the transform also works when the rule definition is an arrow function

tests/fixtures/transforms/new-rule-format/custom-identifier-context.md

@@ -0,0 +1,5 @@
+tests that the transform can handle rules that use an identifier for the "context" object that is not "context", e.g.:
+
+```js
+customContextName.report({ ... });
+```

tests/fixtures/transforms/new-rule-format/fixable.md

@@ -0,0 +1 @@
+tests that the transform can detect that a rule is fixable

tests/fixtures/transforms/new-rule-format/no-schema.md

@@ -0,0 +1 @@
+tests that the transform can handle rules that have no schema being exported

tests/fixtures/transforms/new-rule-format/schema-uses-variables.md

@@ -0,0 +1 @@
+tests that the transform can handle rules that have a schema definition that depends on variables that were declared above it

tests/fixtures/transforms/new-rule-format/simple.md

@@ -0,0 +1 @@
+tests basic functionality of the transform

tests/fixtures/transforms/new-rule-format/with-comments.md

@@ -0,0 +1 @@
+tests that the transform can handle comments in different nodes that will be moved around

tests/fixtures/transforms/new-rule-format/wrapped-in-function.md

@@ -0,0 +1,7 @@
+tests that the transform works when the rule definition is wrapped in a function:
+
+```js
+module.exports = doSomething(function(context) {
+ return { ... };
+});
+```

tests/lib/new-rule-format/new-rule-format.js → tests/lib/transforms.js

@@ -13,7 +13,8 @@ var os = require("os");
 var path = require("path");
 var expect = require("chai").expect;
 
-var newRuleFormatTransform = require("../../../lib/new-rule-format/new-rule-format");
+var fixturesRootPath = path.join(__dirname, "../fixtures/transforms");
+
 
 /**
  * Returns a new string with all the EOL markers from the string passed in
@@ -40,7 +41,7 @@ function normalizeLineEndngs(input) {
  * @private
  */
 function testTransformWithFixture(transform, transformFixturePrefix) {
- var fixtureDir = path.join(__dirname, "../../fixtures/lib/new-rule-format");
+ var fixtureDir = path.join(fixturesRootPath, transform.name);
  var inputPath = path.join(fixtureDir, transformFixturePrefix + ".input.js");
  var source = fs.readFileSync(inputPath, "utf8");
  var expectedOutput = fs.readFileSync(
@@ -50,7 +51,7 @@ function testTransformWithFixture(transform, transformFixturePrefix) {
 
  it("transforms correctly using \"" + transformFixturePrefix + "\" fixture", function() {
 
- var output = transform(
+ var output = transform.fn(
  { path: inputPath, source: source },
  { jscodeshift: jscodeshift },
  {}
@@ -82,41 +83,73 @@ function testTransformWithFixtures(transform, fixtures) {
  });
 }
 
-describe("New Rule Format transform", function() {
- testTransformWithFixtures(newRuleFormatTransform, [
- // tests basic functionality of the transform
- "simple",
-
- // tests that the transform can detect that a rule is fixable
- "fixable",
+/**
+ * Determines if the file name is *.input.js
+ *
+ * @param {string} name - file name
+ * @returns {boolean} - does it match?
+ * @private
+*/
+function inputsFilter(name) {
+ return /\.input\.js/.test(name);
+}
 
- // tests that the transform can handle rules that have no schema being exported
- "no-schema",
+/**
+ * extracts <test-name> from <test-name>.input.js
+ *
+ * @param {string} name - file name
+ * @returns {string} - the test name
+ * @private
+ */
+function extractTestName(name) {
+ return name.split(".").shift();
+}
 
- // tests that the transform can handle rules that use an identifier for the
- // "context" object that is not "context", e.g.:
- // customContextName.report({ ... });
- "custom-identifier-context",
 
- // tests that the transform can handle rules that have a schema definition that
- // depends on variables that were declared above it
- "schema-uses-variables",
+/**
+ * Loads the transform module
+ *
+ * @param {string} name - the transform name
+ * @returns {function} - the module
+ * @private
+ */
+function loadTransformFn(name) {
+ return require("../../lib/transforms/" + name);
+}
 
- // tests that the transform can handle comments in different nodes that will be
- // moved around
- "with-comments",
+/**
+ * loads a transform object
+ *
+ * @param {string} name - the name of the tranform
+ * @returns {object} - a transform object ({name, fn})
+ * @private
+ */
+function loadTransform(name) {
+ return {
+ name: name,
+ fn: loadTransformFn(name)
+ };
+}
 
- // tests that the transform doesn't fail if the rule was already in the new format
- "already-transformed",
+/**
+ * defines a test suite for a transform
+ *
+ * @param {object} transform - {name, fn}
+ * @returns {void}
+ */
+function describeTransform(transform) {
+ describe(transform.name, function() {
+ var fixtureDir = path.join(fixturesRootPath, transform.name);
+ var tests = fs
+ .readdirSync(fixtureDir)
+ .filter(inputsFilter)
+ .map(extractTestName);
+ testTransformWithFixtures(transform, tests);
+ });
+}
 
- // tests that the transform also works when the rule definition is an arrow function
- "arrow-function",
+fs
+.readdirSync(fixturesRootPath)
+.map(loadTransform)
+.forEach(describeTransform);
 
- // tests that the transform works when the rule definition is wrapped in a function:
- //
- // module.exports = doSomething(function(context) {
- // return { ... };
- // });
- "wrapped-in-function"
- ]);
-});