diff --git a/__tests__/find-ruby.test.ts b/__tests__/find-ruby.test.ts
new file mode 100644
index 0000000..44b6ba2
--- /dev/null
+++ b/__tests__/find-ruby.test.ts
@@ -0,0 +1,59 @@
+import * as io from '@actions/io';
+import fs = require('fs');
+import os = require('os');
+import path = require('path');
+
+const toolDir = path.join(__dirname, 'runner', 'tools');
+const tempDir = path.join(__dirname, 'runner', 'temp');
+
+process.env['RUNNER_TOOLSDIRECTORY'] = toolDir;
+process.env['RUNNER_TEMPDIRECTORY'] = tempDir;
+
+import findRubyVersion from '../src/find-ruby';
+
+describe('find-ruby', () => {
+  beforeAll(async () => {
+    await io.rmRF(toolDir);
+    await io.rmRF(tempDir);
+  });
+
+  afterAll(async () => {
+    try {
+      await io.rmRF(toolDir);
+      await io.rmRF(tempDir);
+    } catch {
+      console.log('Failed to remove test directories');
+    }
+  }, 100000);
+
+  it('findRubyVersion throws if cannot find any version of ruby', async () => {
+    let thrown = false;
+    try {
+      await findRubyVersion('>= 2.4');
+    } catch {
+      thrown = true;
+    }
+    expect(thrown).toBe(true);
+  });
+
+  it('findRubyVersion throws version of ruby is not complete', async () => {
+    let thrown = false;
+    const rubyDir: string = path.join(toolDir, 'Ruby', '2.4.6', os.arch());
+    await io.mkdirP(rubyDir);
+    try {
+      await findRubyVersion('>= 2.4');
+    } catch {
+      thrown = true;
+    }
+    expect(thrown).toBe(true);
+  });
+
+  it('findRubyVersion adds ruby bin to PATH', async () => {
+    const rubyDir: string = path.join(toolDir, 'Ruby', '2.4.6', os.arch());
+    await io.mkdirP(rubyDir);
+    fs.writeFileSync(`${rubyDir}.complete`, 'hello');
+    await findRubyVersion('>= 2.4');
+    const binDir = path.join(rubyDir, 'bin');
+    expect(process.env['PATH']!.startsWith(`${binDir};`)).toBe(true);
+  });
+});
diff --git a/__tests__/main.test.ts b/__tests__/main.test.ts
deleted file mode 100644
index 2c750df..0000000
--- a/__tests__/main.test.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-import findRuby, {Platform} from '../src/find-ruby';
-
-describe('TODO - Add a test suite', () => {
-  it('TODO - Add a test', async () => {
-    findRuby({addToPath: 'true', version: '>= 2.4'}, Platform.Windows);
-  });
-});
diff --git a/lib/find-ruby.js b/lib/find-ruby.js
index 5624f7b..7827b14 100644
--- a/lib/find-ruby.js
+++ b/lib/find-ruby.js
@@ -15,6 +15,7 @@ var __importStar = (this && this.__importStar) || function (mod) {
     return result;
 };
 Object.defineProperty(exports, "__esModule", { value: true });
+const core = __importStar(require("@actions/core"));
 const exec = __importStar(require("@actions/exec"));
 const tc = __importStar(require("@actions/tool-cache"));
 const path = __importStar(require("path"));
@@ -33,6 +34,7 @@ function default_1(version) {
             const dest = '/usr/bin/ruby';
             exec.exec('sudo ln', ['-sf', path.join(toolPath, 'ruby'), dest]); // replace any existing
         }
+        core.addPath(toolPath);
     });
 }
 exports.default = default_1;
diff --git a/src/find-ruby.ts b/src/find-ruby.ts
index 3c6c9ae..45178bd 100644
--- a/src/find-ruby.ts
+++ b/src/find-ruby.ts
@@ -1,3 +1,4 @@
+import * as core from '@actions/core';
 import * as exec from '@actions/exec';
 import * as tc from '@actions/tool-cache';
 import * as path from 'path';
@@ -20,4 +21,6 @@ export default async function(version: string) {
     const dest: string = '/usr/bin/ruby';
     exec.exec('sudo ln', ['-sf', path.join(toolPath, 'ruby'), dest]); // replace any existing
   }
+
+  core.addPath(toolPath);
 }