diff --git a/packages/svelte2tsx/test/helpers.ts b/packages/svelte2tsx/test/helpers.ts
index 15f0c0bf9..a7dbe1855 100644
--- a/packages/svelte2tsx/test/helpers.ts
+++ b/packages/svelte2tsx/test/helpers.ts
@@ -8,7 +8,7 @@ export function benchmark(fn: () => void) {
     return -Date.now() + (fn(), Date.now());
 }
 
-export function readFileSync(path: string) {
+function readFileSync(path: string) {
     return fs.existsSync(path)
         ? fs.readFileSync(path, 'utf-8').replace(/\r\n/g, '\n').replace(/\s+$/, '')
         : null;
@@ -122,22 +122,19 @@ type TransformSampleFn = (
     }
 ) => ReturnType<typeof htmlx2jsx | typeof svelte2tsx>;
 
-export function test_samples(dir: string, transform: TransformSampleFn, tsx: 'jsx' | 'tsx') {
+export function test_samples(dir: string, transform: TransformSampleFn, jsx: 'jsx' | 'tsx') {
     for (const sample of each_sample(dir)) {
         const svelteFile = sample.folder.find((f) => f.endsWith('.svelte'));
 
         sample.check_dir({
             required: ['*.svelte'],
-            allowed: ['expected.js', `expected.${tsx}`, 'test.js']
+            allowed: ['expected.js', `expected.${jsx}`, 'expected.error.json']
         });
 
-        const shouldGenerateExpected = !sample.has(`expected.${tsx}`);
+        const shouldGenerateExpected = !sample.has(`expected.${jsx}`);
+        const shouldGenerateError = sample.get('expected.error.json') === '';
 
         sample.it(function () {
-            if (sample.has('test.js')) {
-                sample.eval('test.js');
-                return;
-            }
             const input = sample.get(svelteFile);
             const config = {
                 fileName: svelteFile,
@@ -145,12 +142,34 @@ export function test_samples(dir: string, transform: TransformSampleFn, tsx: 'js
                 emitOnTemplateError: false
             };
 
+            if (sample.has('expected.error.json')) {
+                let hadError = false;
+                try {
+                    transform(input, config);
+                } catch (error) {
+                    hadError = true;
+                    if (shouldGenerateError) {
+                        sample.generate(
+                            'expected.error.json',
+                            JSON.stringify(error, null, 4) + '\n'
+                        );
+                    } else {
+                        assert.deepEqual(
+                            JSON.parse(sample.get('expected.error.json')),
+                            JSON.parse(JSON.stringify(error))
+                        );
+                    }
+                }
+                config.emitOnTemplateError = true;
+                assert(hadError, `Expected a template error but got none`);
+            }
+
             const output = transform(input, config);
 
             if (shouldGenerateExpected) {
-                sample.generate(`expected.${tsx}`, output.code);
+                sample.generate(`expected.${jsx}`, output.code);
             } else {
-                assert.strictEqual(output.code, sample.get(`expected.${tsx}`));
+                assert.strictEqual(output.code, sample.get(`expected.${jsx}`));
             }
 
             if (sample.has('expected.js')) {
@@ -165,13 +184,3 @@ export function* each_sample(dir: string) {
         yield new Sample(dir, name);
     }
 }
-
-/**
- *
- * @param {string} dirPath
- */
-export function get_input_content(dirPath) {
-    const filename = fs.readdirSync(dirPath).find((f) => f.endsWith('.svelte'));
-    const content = readFileSync(`${dirPath}/${filename}`);
-    return { filename, content };
-}
diff --git a/packages/svelte2tsx/test/htmlx2jsx/index.ts b/packages/svelte2tsx/test/htmlx2jsx/index.ts
index 64b4aa6eb..3e64e4108 100644
--- a/packages/svelte2tsx/test/htmlx2jsx/index.ts
+++ b/packages/svelte2tsx/test/htmlx2jsx/index.ts
@@ -2,5 +2,11 @@ import { htmlx2jsx } from '../build/htmlxtojsx';
 import { test_samples } from '../helpers';
 
 describe('htmlx2jsx', () => {
-    test_samples(__dirname, htmlx2jsx, 'jsx');
+    test_samples(
+        __dirname,
+        (input, { emitOnTemplateError }) => {
+            return htmlx2jsx(input, { emitOnTemplateError });
+        },
+        'jsx'
+    );
 });
diff --git a/packages/svelte2tsx/test/htmlx2jsx/samples/editing-mustache/expected.error.json b/packages/svelte2tsx/test/htmlx2jsx/samples/editing-mustache/expected.error.json
new file mode 100644
index 000000000..afb677f97
--- /dev/null
+++ b/packages/svelte2tsx/test/htmlx2jsx/samples/editing-mustache/expected.error.json
@@ -0,0 +1,16 @@
+{
+    "name": "ParseError",
+    "code": "parse-error",
+    "start": {
+        "line": 1,
+        "column": 8,
+        "character": 8
+    },
+    "end": {
+        "line": 1,
+        "column": 8,
+        "character": 8
+    },
+    "pos": 8,
+    "frame": "1: {abc.   }\n           ^\n2: {abc?. }\n3: {abc ?}"
+}
diff --git a/packages/svelte2tsx/test/htmlx2jsx/samples/editing-mustache/test.js b/packages/svelte2tsx/test/htmlx2jsx/samples/editing-mustache/test.js
deleted file mode 100644
index 970b8e422..000000000
--- a/packages/svelte2tsx/test/htmlx2jsx/samples/editing-mustache/test.js
+++ /dev/null
@@ -1,26 +0,0 @@
-const assert = require('assert');
-const { htmlx2jsx } = require('../../../build/htmlxtojsx');
-const { get_input_content, readFileSync } = require('../../../helpers');
-
-module.exports = function () {
-    const input = get_input_content(__dirname);
-
-    assert.throws(
-        () => {
-            htmlx2jsx(input.content);
-        },
-        {
-            name: 'ParseError',
-            code: 'parse-error',
-            start: { line: 1, column: 8, character: 8 },
-            end: { line: 1, column: 8, character: 8 },
-            frame: '1: {abc.   }\n           ^\n2: {abc?. }\n3: {abc ?}'
-        }
-    );
-
-    const expected_path = `${__dirname}/expected.jsx`;
-    assert.strictEqual(
-        htmlx2jsx(input.content, { emitOnTemplateError: true }).code,
-        readFileSync(expected_path).toString()
-    );
-};
diff --git a/packages/svelte2tsx/test/svelte2tsx/samples/editing-mustache/expected.error.json b/packages/svelte2tsx/test/svelte2tsx/samples/editing-mustache/expected.error.json
new file mode 100644
index 000000000..95cf71155
--- /dev/null
+++ b/packages/svelte2tsx/test/svelte2tsx/samples/editing-mustache/expected.error.json
@@ -0,0 +1,16 @@
+{
+    "name": "ParseError",
+    "code": "parse-error",
+    "start": {
+        "line": 1,
+        "column": 4,
+        "character": 4
+    },
+    "end": {
+        "line": 1,
+        "column": 4,
+        "character": 4
+    },
+    "pos": 4,
+    "frame": "1: {a?.}\n       ^"
+}
diff --git a/packages/svelte2tsx/test/svelte2tsx/samples/editing-mustache/test.js b/packages/svelte2tsx/test/svelte2tsx/samples/editing-mustache/test.js
deleted file mode 100644
index 429136706..000000000
--- a/packages/svelte2tsx/test/svelte2tsx/samples/editing-mustache/test.js
+++ /dev/null
@@ -1,29 +0,0 @@
-const assert = require('assert');
-const svelte2tsx = require('../../../build/index');
-const { get_input_content, readFileSync } = require('../../../helpers');
-
-module.exports = function () {
-    const input = get_input_content(__dirname);
-
-    assert.throws(
-        () => {
-            svelte2tsx(input.content);
-        },
-        {
-            name: 'ParseError',
-            code: 'parse-error',
-            start: { line: 1, column: 4, character: 4 },
-            end: { line: 1, column: 4, character: 4 },
-            frame: '1: {a?.}\n       ^'
-        }
-    );
-
-    const expected_path = `${__dirname}/expected.tsx`;
-    assert.strictEqual(
-        svelte2tsx(input.content, {
-            emitOnTemplateError: true,
-            filename: input.filename
-        }).code,
-        readFileSync(expected_path).toString()
-    );
-};