Warn if runSass args do not match newer API

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## UNRELEASED
 
+- FEATURE: Validate `runSass` arguments and warn if using v6 API.
 - DOCUMENTATION: Add note that `{ style: 'compressed' }` is not supported.
 - DOCUMENTATION: Add note about possible Jest error and workaround.
 - INTERNAL: Update dependencies

src/index.ts

@@ -80,6 +80,13 @@ export const runSass = function (
     sassOpts.loadPaths = [sassPath];
   }
 
+  // Warn if arguments match v6 API
+  if (typeof src !== 'string' || !trueOptions.describe || !trueOptions.it) {
+    throw new Error(
+      'The arguments provided to `runSass` do not match the new API introduced in True v7. Refer to the v7 release notes for migration documentation: https://github.com/oddbird/true/releases/tag/v7.0.0',
+    );
+  }
+
   const compiler = trueOpts.sourceType === 'string' ? compileString : compile;
   const parsedCss = compiler(src, sassOpts).css;
   const modules = parse(parsedCss, trueOpts.contextLines);

test/main.test.js

@@ -33,6 +33,31 @@ describe('#fail', () => {
 });
 
 describe('#runSass', () => {
+  it('throws if arguments do not match newer API', () => {
+    const sass = [
+      '@use "true" as *;',
+      '@include test-module("Module") {',
+      '  @include test("Test") {',
+      '    @include assert("Assertion") {',
+      '      @include output() {',
+      '        height: 10px;',
+      '      }',
+      '      @include expect() {',
+      '        height: 10px;',
+      '      }',
+      '    }',
+      '  }',
+      '}',
+    ].join('\n');
+    const mock = function (name, cb) {
+      cb();
+    };
+    const attempt = function () {
+      sassTrue.runSass({ data: sass }, { describe: mock, it: mock });
+    };
+    expect(attempt).to.throw('do not match the new API');
+  });
+
   it('throws AssertionError on failure', () => {
     const sass = [
       '@use "true";',