diff --git a/app/services/project-user.js b/app/services/project-user.js
index f92509b47..d4dbd94b9 100644
--- a/app/services/project-user.js
+++ b/app/services/project-user.js
@@ -6,6 +6,8 @@ export default Service.extend({
   flashMessages: service(),
   store: service(),
 
+  flashOptions: { fixed: true, sticky: false, timeout: 5000 },
+
   joinProject(project) {
     let user = get(this, 'currentUser.user');
     let store = get(this, 'store');
@@ -14,11 +16,15 @@ export default Service.extend({
 
     return store.createRecord('project-user', projectUser)
       .save()
-      .then(() => this._flashSuccess('Your request has been sent.'));
+      .then(() => this._flashSuccess('Your request has been sent.'))
+      .catch(() => this._flashError('Your request has not been sent.'));
   },
 
   _flashSuccess(message) {
-    let options = { fixed: true, sticky: false, timeout: 5000 };
-    get(this, 'flashMessages').clearMessages().success(message, options);
+    get(this, 'flashMessages').clearMessages().success(message, get(this, 'flashOptions'));
+  },
+
+  _flashError(message) {
+    get(this, 'flashMessages').clearMessages().danger(message, get(this, 'flashOptions'));
   }
 });
diff --git a/tests/unit/services/project-user-test.js b/tests/unit/services/project-user-test.js
index 97e986abe..382781d1b 100644
--- a/tests/unit/services/project-user-test.js
+++ b/tests/unit/services/project-user-test.js
@@ -1,15 +1,91 @@
+import RSVP from 'rsvp';
+import { set } from '@ember/object';
 import { moduleFor, test } from 'ember-qunit';
 
 moduleFor('service:project-user', 'Unit | Service | project user', {
-  // Specify the other units that are required for this test.
   needs: [
     'service:current-user',
-    'service:flash-messages'
+    'service:flash-messages',
+    'service:session',
+    'service:metrics'
   ]
 });
 
-// Replace this with your real tests.
-test('it exists', function(assert) {
+test('it creates a new projectUser with properties', function(assert) {
+  assert.expect(3);
+  let done = assert.async();
   let service = this.subject();
-  assert.ok(service);
+  let user = { id: 1 };
+  let project = { title: 'Code Corps' };
+  let projectUser = { project, user, role: 'pending' };
+
+  let mockCurrentUser = { user };
+
+  let mockStore = {
+    createRecord(modelName, inputProperties) {
+      return {
+        save() {
+          assert.equal(modelName, 'project-user');
+          assert.deepEqual(inputProperties, projectUser);
+          return RSVP.resolve(projectUser);
+        }
+      };
+    }
+  };
+
+  // test doesn't care what the message is, just that it was called
+  // need to support function chaining because actual flash-messages
+  // service does function chaining and our component calls to clear all messages first
+  // so the fake needs to support that.
+
+  let mockFlashMessage = {
+    success() {
+      assert.ok(true);
+      return this;
+    },
+    clearMessages() {
+      return this;
+    }
+  };
+
+  set(service, 'currentUser', mockCurrentUser);
+  set(service, 'flashMessages', mockFlashMessage);
+  set(service, 'store', mockStore);
+
+  service.joinProject(project).then(() => {
+    done();
+  });
+});
+
+test('it sends an error flash message if joinProject fails', function(assert) {
+  assert.expect(1);
+  let service = this.subject();
+  let done = assert.async();
+
+  let mockStore = {
+    createRecord() {
+      return {
+        save() {
+          return RSVP.reject();
+        }
+      };
+    }
+  };
+
+  let mockFlashMessage = {
+    danger() {
+      assert.ok(true);
+      return this;
+    },
+    clearMessages() {
+      return this;
+    }
+  };
+
+  set(service, 'flashMessages', mockFlashMessage);
+  set(service, 'store', mockStore);
+
+  service.joinProject().then(() => {
+    done();
+  });
 });