Add tests

Author: meech-ward

.github/workflows/build.yml

@@ -0,0 +1,24 @@
+name: test-async-core-bluetooth
+run-name: ${{ github.actor }} is running tests
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+jobs:
+  build:
+    runs-on: macos-latest
+
+    steps:
+      - uses: SwiftyLab/setup-swift@latest
+
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Build
+        run: swift build
+
+      - name: Test
+        run: swift test 

README.md

@@ -1,5 +1,7 @@
 # AsyncObservable
 
+![Build and Test](https://github.com/meech-ward/AsyncObservable/actions/workflows/build.yml/badge.svg)
+
 [![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Fmeech-ward%2FAsyncObservable%2Fbadge%3Ftype%3Dswift-versions)](https://swiftpackageindex.com/meech-ward/AsyncObservable)
 
 [![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Fmeech-ward%2FAsyncObservable%2Fbadge%3Ftype%3Dplatforms)](https://swiftpackageindex.com/meech-ward/AsyncObservable)