test: Implement Phase 1 - Testing and error handling improvements

Add comprehensive test suite:
- JSON parsing tests for wrapped/unwrapped formats
- Resource calculation and leftover computation tests
- Error handling tests for invalid inputs
- Test coverage: 9 test cases, all passing

Improve error handling:
- Add proper error handling for strconv.ParseInt (main.go:141-148)
- Provide clear error messages for invalid CPU/Memory values

Add CI/CD infrastructure:
- Create GitHub Actions workflow for automated testing
- Include go test, go vet, go fmt checks
- Add build verification step

Other improvements:
- Update .gitignore to exclude coverage.out
- Format code with gofmt

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: claude

.github/workflows/test.yml

@@ -0,0 +1,72 @@
+name: test
+on:
+  push:
+    branches:
+      - main
+      - claude/**
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: "go.mod"
+
+      - name: Run tests
+        run: go test -v -race -coverprofile=coverage.out -covermode=atomic ./...
+
+      - name: Display coverage
+        run: go tool cover -func=coverage.out
+
+      - name: Check coverage threshold
+        run: |
+          coverage=$(go tool cover -func=coverage.out | grep total | awk '{print $3}' | sed 's/%//')
+          echo "Total coverage: ${coverage}%"
+          if (( $(echo "$coverage < 50" | bc -l) )); then
+            echo "Warning: Coverage is below 50%"
+          fi
+
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: "go.mod"
+
+      - name: Run go vet
+        run: go vet ./...
+
+      - name: Run go fmt
+        run: |
+          if [ -n "$(gofmt -l .)" ]; then
+            echo "Go code is not formatted:"
+            gofmt -d .
+            exit 1
+          fi
+
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: "go.mod"
+
+      - name: Build
+        run: go build -v -o bin/ecsource main.go
+
+      - name: Verify binary
+        run: ./bin/ecsource --version

.gitignore

@@ -1 +1,2 @@
 bin/ecsource
+coverage.out

main.go

@@ -138,8 +138,14 @@ func main() {
 		allMemoryReservation += containerDefinition.MemoryReservation
 	}
 	table.Append([]string{"sum of all container", fmt.Sprintf("%d", allCPU), fmt.Sprintf("%d", allMemory), fmt.Sprintf("%d", allMemoryReservation)})
-	taskCPU, _ := strconv.ParseInt(taskDefinition.CPU, 10, 64)
-	taskMemory, _ := strconv.ParseInt(taskDefinition.Memory, 10, 64)
+	taskCPU, err := strconv.ParseInt(taskDefinition.CPU, 10, 64)
+	if err != nil {
+		log.Fatalf("failed to parse task CPU '%s': %v", taskDefinition.CPU, err)
+	}
+	taskMemory, err := strconv.ParseInt(taskDefinition.Memory, 10, 64)
+	if err != nil {
+		log.Fatalf("failed to parse task Memory '%s': %v", taskDefinition.Memory, err)
+	}
 
 	leftoverCPU := taskCPU - allCPU
 	leftoverMemory := taskMemory - allMemory