Added the action's code

Author: guyarb

README.md

@@ -1,2 +1,48 @@
 # golang-test-annoations
 A github action which annotates failed tests.
+
+![GitHub Annotations](./static/example.png)
+
+## How to use
+
+Add to your workflow the following contents:
+
+```yaml
+name: workflow
+
+on:
+  push:
+    branches: [ '**' ]
+  pull_request:
+    branches: [ '**' ]
+
+jobs:
+  full_ci:
+    runs-on: ubuntu-18.04
+
+    steps:
+      - name : checkout
+        uses: actions/checkout@v2
+
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '1.14'
+
+      - name: run tests
+        run: go test -json ./... > test.json
+
+      - name: annotate tests
+        if: always()
+        uses: guyarb/[email protected]
+        with:
+          test-results: test.json
+```
+
+## Development of this action
+
+1. Fork this repo.
+2. Create a branch with your feature/bugfix.
+3. Open a PR to me.
+
+## Issues
+Please open issues for any bug or suggestion you have.

action.yml

@@ -0,0 +1,13 @@
+name: 'Golang Test Annotations'
+description: 'Given a test output of go test, the failed tests will be annotated.'
+inputs:
+  test-results:  # Path of the test results
+    description: 'The path of the go test results'
+    required: true
+    default: 'test.json'
+runs:
+  using: 'node12'
+  main: 'index.js'
+branding:
+  icon: "check"
+  color: "green"

index.js

@@ -0,0 +1,42 @@
+const core = require('@actions/core');
+const lineReader = require('line-by-line');
+
+try {
+	const testResultsPath = core.getInput('test-results');
+
+	var obj = new Object();
+	var lr = new lineReader(testResultsPath);
+	lr.on('line', function(line) {
+		const currentLine = JSON.parse(line);
+		var testName = currentLine.Test;
+		if (typeof testName === "undefined") {
+			return;
+		}
+
+		var output = currentLine.Output;
+		if (typeof output === "undefined") {
+			return;
+		}
+		output = output.replace("\n", "%0A").replace("\r", "%0D")
+		// Removing the github.com/owner/reponame
+		var packageName = currentLine.Package.split("/").slice(3).join("/");
+		var newEntry = packageName + "/" + testName;
+		if (!obj.hasOwnProperty(newEntry)) {
+			obj[newEntry] = output;
+		} else {
+			obj[newEntry] += output;
+		}
+	});
+	lr.on('end', function() {
+		for (const [key, value] of Object.entries(obj)) {
+			if (value.includes("FAIL") && value.includes("_test.go")) {
+				const parts = value.split("%0A")[1].trim().split(":");
+				const file = key.split("/").slice(0, -1).join("/") + "/" + parts[0];
+				const lineNumber = parts[1];
+				core.info(`::error file=${file},line=${lineNumber}::${value}`)
+			}
+		}
+	});
+} catch (error) {
+	core.setFailed(error.message);
+}