app: Adding test for new docker client versions' capability prefix

agent/app/agent_capability_test.go

@@ -339,3 +339,49 @@ func TestAWSVPCBlockInstanceMetadataWhenTaskENIIsDisabled(t *testing.T) {
 		}
 	}
 }
+
+func TestNewDockerVersionsCapabilityPrefix(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+
+	client := engine.NewMockDockerClient(ctrl)
+	conf := &config.Config{
+		PrivilegedDisabled:true,
+	}
+
+	gomock.InOrder(
+		client.EXPECT().SupportedVersions().Return([]dockerclient.DockerVersion{
+			dockerclient.Version_1_21,
+			dockerclient.Version_1_25,
+			dockerclient.Version_1_26,
+		}),
+	)
+	client.EXPECT().KnownVersions().Return(nil)
+
+	expectedCapabilityNames := []string{
+		"com.amazonaws.ecs.capability.docker-remote-api.1.21",
+		"ecs.capability.docker-remote-api.1.25",
+		"ecs.capability.docker-remote-api.1.26",
+	}
+
+	var expectedCapabilities []*ecs.Attribute
+	for _, name := range expectedCapabilityNames {
+		expectedCapabilities = append(expectedCapabilities,
+			&ecs.Attribute{Name: aws.String(name)})
+	}
+
+	ctx, cancel := context.WithCancel(context.TODO())
+	// Cancel the context to cancel async routines
+	defer cancel()
+	agent := &ecsAgent{
+		ctx:          ctx,
+		dockerClient: client,
+		cfg:          conf,
+	}
+	capabilities := agent.capabilities()
+
+	for i, expected := range expectedCapabilities {
+		assert.Equal(t, aws.StringValue(expected.Name), aws.StringValue(capabilities[i].Name))
+		assert.Equal(t, aws.StringValue(expected.Value), aws.StringValue(capabilities[i].Value))
+	}
+}