Women Who Go: Building a basic API in Go - Sample Tests

handlers_test.go

package main

import (
	"net/http/httptest"
	"testing"
	"io/ioutil"
	"strings"
)

/**
 Below are some basic tests for the handlers used in this tutorial:
 https://thenewstack.io/make-a-restful-json-api-go/
*/

func TestIndex(t *testing.T) {
	tests := []struct {
		description string
		endpoint string
		expectedCode int
		expectedOutput string
	}{
		{
			description: "success",
			endpoint: "/",
			expectedCode: 200,
			expectedOutput: "Welcome!",
		},
	}

	for _, tc := range tests {
		req := httptest.NewRequest("GET", tc.endpoint, nil) // creating an http request
		w := httptest.NewRecorder() // creating a response writer

		Index(w, req) // calling the handler 
    
		if tc.expectedCode != w.Code {
			t.Fatalf("Expected %s, but got %s", tc.expectedCode, w.Code)
		}

		b, err := ioutil.ReadAll(w.Body)
		if err != nil {
			t.Fatalf("Error getting response body: %+v", err)
		}

		output := strings.TrimSpace(string(b))

		if tc.expectedOutput != output {
			t.Fatalf("Expected %s, but got %s", tc.expectedOutput, output)
		}
	}
}

func TestTodoIndex(t *testing.T) {
	tests := []struct {
		description string
		endpoint string
		expectedCode int
		expectedOutput string
	}{
		{
			description: "success",
			endpoint: "/todos",
			expectedCode: 200,
			expectedOutput: `[{"name":"Write presentation","completed":false,"due":"0001-01-01T00:00:00Z"},{"name":"Host meetup","completed":false,"due":"0001-01-01T00:00:00Z"}]`,
		},
	}

	for _, tc := range tests {
		req  := httptest.NewRequest("GET", "/todos", nil)
		w := httptest.NewRecorder()

		TodoIndex(w, req)

		if tc.expectedCode != w.Code {
			t.Fatalf("Expected %s, but got %s", tc.expectedCode, w.Code)
		}

		b, err := ioutil.ReadAll(w.Body)
		if err != nil {
			t.Fatalf("Error getting response body: %+v", err)
		}

		output := strings.TrimSpace(string(b))

		if tc.expectedOutput != output {
			t.Fatalf("Expected %s, but got %s", tc.expectedOutput, output)
		}
	}
}

/*
 Try adding error responses to your handler, and then
 add test cases for those errors. For example, check the id length in TodoShow:
 
 func TodoShow(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	todoId := vars["todoId"]
	if len(todoId) < 4 {
		http.Error(w, "INVALID_TODO_ID", 400)
		return
	}
	fmt.Fprintln(w, "Todo show:", todoId)
}

Then you could add a test for TodoShow that looks like:

func TestTodoShow(t *testing.T) {
	tests := []struct {
		description string
		endpoint string
		id string
		expectedCode int
		expectedOutput string
	}{
		{
			description: "failure - invalid id",
			endpoint: "/todos/bad",
			id: "bad",
			expectedCode: 400,
			expectedOutput: "INVALID_TODO_ID",
		},
		{
			description: "success",
			endpoint: "/todos/goodID",
			id: "goodID",
			expectedCode: 200,
			expectedOutput: "Todo show: goodID",
		},

	}

	for _, tc := range tests {

		req  := httptest.NewRequest("GET", tc.endpoint, nil)
		w := httptest.NewRecorder()


   		// The reason we have to define a new router here
   		// is that there currently isn't a good way (that I found)
   		// to pass the route params to the handler in a unit test. 
   		// See http://bit.ly/2DCdOtT for a few other options and more explanation.
		NewRouter().ServeHTTP(w, req)

		if tc.expectedCode != w.Code {
			t.Fatalf("Expected %s, but got %s", tc.expectedCode, w.Code)
		}

		b, err := ioutil.ReadAll(w.Body)
		if err != nil {
			t.Fatalf("Error getting response body: %+v", err)
		}

		output := strings.TrimSpace(string(b))

		if tc.expectedOutput != output {
			t.Fatalf("Expected %s, but got %s", tc.expectedOutput, output)
		}
	}
}
*/