diff --git a/bin/test.js b/bin/test.js
index 1380a512..e19a2ad9 100644
--- a/bin/test.js
+++ b/bin/test.js
@@ -51,6 +51,16 @@ if (checkCoverage) {
   process.exit(run.status);
 }
 
+const checkDebug = flagArgs.indexOf('--debug') >= 0;
+
+if (checkDebug) {
+  env.DEBUG = 'debug';
+}
+
+if (env.DEBUG) {
+  console.log('poll result', result);
+}
+
 const run = cp.spawnSync(
   npmBinScript('mocha'),
   [...testFiles, ...flagArgs],
diff --git a/bin/test_api.js b/bin/test_api.js
new file mode 100644
index 00000000..2eb3fc3e
--- /dev/null
+++ b/bin/test_api.js
@@ -0,0 +1,49 @@
+/**
+ * Copyright (c) 2019 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+const cp = require('child_process');
+const path = require('path');
+
+
+// Add `out` to the NODE_PATH so absolute paths can be resolved.
+const env = { ...process.env };
+env.NODE_PATH = path.resolve(__dirname, '../out');
+
+let testFiles = [
+  './addons/**/out/*api.js',
+  './out-test/**/*api.js',
+];
+
+
+let flagArgs = [];
+
+if (process.argv.length > 2) {
+  const args = process.argv.slice(2);
+  flagArgs = args.filter(e => e.startsWith('--'));
+  // ability to inject particular test files via
+  // yarn test [testFileA testFileB ...]
+  files = args.filter(e => !e.startsWith('--'));
+  if (files.length) {
+    testFiles = files;
+  }
+}
+
+env.DEBUG = flagArgs.indexOf('--debug') >= 0 ? 'debug' : '';
+
+const run = cp.spawnSync(
+  npmBinScript('mocha'),
+  [...testFiles, ...flagArgs],
+  {
+    cwd: path.resolve(__dirname, '..'),
+    env,
+    stdio: 'inherit'
+  }
+);
+
+function npmBinScript(script) {
+  return path.resolve(__dirname, `../node_modules/.bin/` + (process.platform === 'win32' ? `${script}.cmd` : script));
+}
+
+process.exit(run.status);
diff --git a/package.json b/package.json
index 956cdbb1..192d8ca1 100644
--- a/package.json
+++ b/package.json
@@ -14,7 +14,7 @@
     "lint": "tslint 'src/**/*.ts' 'addons/*/src/**/*.ts'",
     "test": "npm run test-unit",
     "posttest": "npm run lint",
-    "test-api": "mocha \"**/*.api.js\"",
+    "test-api": "node ./bin/test_api.js",
     "test-unit": "node ./bin/test.js",
     "test-unit-coverage": "node ./bin/test.js --coverage",
     "build": "tsc -b ./tsconfig.all.json",
diff --git a/test/api/TestUtils.ts b/test/api/TestUtils.ts
index d3674812..ba2c43fd 100644
--- a/test/api/TestUtils.ts
+++ b/test/api/TestUtils.ts
@@ -11,6 +11,11 @@ export async function pollFor<T>(page: puppeteer.Page, evalOrFn: string | (() =>
     await preFn();
   }
   const result = typeof evalOrFn === 'string' ? await page.evaluate(evalOrFn) : await evalOrFn();
+
+  if (process.env.DEBUG) {
+    console.log('pollFor result: ', result);
+  }
+
   if (!deepEqual(result, val)) {
     return new Promise<void>(r => {
       setTimeout(() => r(pollFor(page, evalOrFn, val, preFn)), 1);