feat: add wait grp exercise

internal/exercises/catalog.yaml

@@ -201,3 +201,11 @@ projects:
     - "Use Go's `time.Unix()` to convert an epoch to time."
     - "Use `t.Unix()` to convert time back to epoch."
     - "Remember Go’s `time.Parse` can help parse date strings."
+
+- slug: 37_waitGroup
+  title: "WaitGroups"
+  difficulty: beginner
+  topics: ["waitGroup", "go"]
+  hints:
+    - "Use Go's waitGroups inorder to wait for the goroutines"
+

internal/exercises/solutions/37_waitGroup/waitGroup.go

@@ -0,0 +1,23 @@
+package waitgroup
+
+import (
+	"sync"
+)
+
+// TODO: Implement these functions so tests pass
+
+// The waitGroup in Go is used to wait for a collection of goroutines to finish executing
+
+func worker(wg *sync.WaitGroup, result *string) {
+	defer wg.Done()
+	*result = "Worker done"
+}
+
+func waitGroup() string {
+	var wg sync.WaitGroup
+	result := ""
+	wg.Add(1)
+	go worker(&wg, &result)
+	wg.Wait()
+	return result
+}

internal/exercises/templates/37_waitGroup/waitGroup.go

@@ -0,0 +1,18 @@
+package waitgroup
+
+import (
+	"sync"
+)
+
+// TODO: Implement these functions so tests pass
+
+func worker(wg *sync.WaitGroup, result *string) {
+	*result = "Worker done"
+}
+
+func waitGroup() string {
+	var wg sync.WaitGroup
+	result := ""
+	go worker(&wg, &result)
+	return result
+}

internal/exercises/templates/37_waitGroup/waitGroup_test.go

@@ -0,0 +1,11 @@
+package waitgroup
+
+import "testing"
+
+func TestHello(t *testing.T) {
+	got := waitGroup()
+	want := "Worker done"
+	if got != want {
+		t.Fatalf("waitGroup() = %q, want %q", got, want)
+	}
+}