diff --git a/.circleci/config.yml b/.circleci/config.yml
index 28280c6..74caed0 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -123,10 +123,10 @@ commands:
           command: npm pack
       - run:
           name: Setup Import Test
-          command: echo $PWD && cd .. && mkdir test-import && cp -a project/test-import/ test-import/test-import/ && cd test-import && npm init -y && npm i ../project/is-promise-2.2.2.tgz
+          command: echo $PWD && cd .. && cp -a project/test-import/ test-import/ && cd test-import && npm i && npm i ../project/is-promise-2.2.2.tgz
       - run:
           name: Test Import
-          command: cd ../test-import && node test-import/test.js
+          command: cd ../test-import && npm test
 
   publish-dry-run:
     steps:
diff --git a/package.json b/package.json
index c8a6680..eb3551f 100644
--- a/package.json
+++ b/package.json
@@ -8,7 +8,8 @@
   },
   "files": [
     "index.js",
-    "index.mjs"
+    "index.mjs",
+    "index.d.ts"
   ],
   "repository": {
     "type": "git",
diff --git a/test-import/index.ts b/test-import/index.ts
new file mode 100644
index 0000000..2ef2089
--- /dev/null
+++ b/test-import/index.ts
@@ -0,0 +1,9 @@
+import * as ta from 'type-assertions';
+import isPromise from 'is-promise';
+
+declare const x: number | Promise<string>;
+if (isPromise(x)) {
+  ta.assert<ta.Equal<typeof x, Promise<string>>>();
+} else {
+  ta.assert<ta.Equal<typeof x, number>>();
+}
\ No newline at end of file
diff --git a/test-import/package.json b/test-import/package.json
new file mode 100644
index 0000000..7090b05
--- /dev/null
+++ b/test-import/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "is-promise-test-import",
+  "private": true,
+  "@rollingversions/ignore": true,
+  "scripts": {
+    "test": "node test"
+  },
+  "dependencies": {
+    "type-assertions": "^1.1.0"
+  }
+}
diff --git a/test-import/test.js b/test-import/test.js
index 50ef5e6..9d0ef7f 100644
--- a/test-import/test.js
+++ b/test-import/test.js
@@ -31,5 +31,11 @@ console.log('CommonJS tests passed')
 
 if(parseInt(process.version.split('.')[0].substr(1), 10) >= 14) {
   const result = require('child_process').spawnSync('node', ['test.mjs'], {cwd: __dirname, stdio: 'inherit'});
-  process.exit(result.status);
+  if (result.status) process.exit(result.status);
+}
+
+if(parseInt(process.version.split('.')[0].substr(1), 10) >= 12) {
+  const result = require('child_process').spawnSync('npx', ['typescript', 'index.ts'], {cwd: __dirname, stdio: 'inherit'});
+  if (result.status) process.exit(result.status);
+  console.log('TypeScript tests passed');
 }
\ No newline at end of file
diff --git a/test-import/tsconfig.json b/test-import/tsconfig.json
new file mode 100644
index 0000000..8bf3bdd
--- /dev/null
+++ b/test-import/tsconfig.json
@@ -0,0 +1,7 @@
+{
+  "compilerOptions": {
+    "noImplicitAny": true,
+    "skipLibCheck": false,
+    "strict": true
+  }
+}
\ No newline at end of file