feat: add Delete method for hashmap

datastructure/hashmap/hashmap_test.go

@@ -7,7 +7,7 @@ import (
 )
 
 func TestHashMap_PutAndGet(t *testing.T) {
-	assert := internal.NewAssert(t, "TestHashMap_Get")
+	assert := internal.NewAssert(t, "TestHashMap_PutAndGet")
 
 	hm := NewHashMap()
 
@@ -18,3 +18,25 @@ func TestHashMap_PutAndGet(t *testing.T) {
 	hm.Put("abc", 4)
 	assert.Equal(4, hm.Get("abc"))
 }
+
+func TestHashMap_Delete(t *testing.T) {
+	assert := internal.NewAssert(t, "TestHashMap_Delete")
+
+	hm := NewHashMap()
+
+	hm.Put("abc", 3)
+	assert.Equal(3, hm.Get("abc"))
+
+	hm.Delete("abc")
+	assert.IsNil(hm.Get("abc"))
+}
+
+func TestHashMap_Contains(t *testing.T) {
+	assert := internal.NewAssert(t, "TestHashMap_Contains")
+
+	hm := NewHashMap()
+	assert.Equal(false, hm.Contains("abc"))
+
+	hm.Put("abc", 3)
+	assert.Equal(true, hm.Contains("abc"))
+}