Adds client implementation for football API and test cases (league da…

…ta). Refs #1

pkg/clients/football.go

@@ -0,0 +1,84 @@
+package clients
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"net/http"
+	"time"
+)
+
+const BASE_API_URL = "http://api.football-data.org/v4/"
+
+type Area struct {
+	ID   int64  `json:"id"`
+	Name string `json:"name"`
+	Code string `json:"code"`
+}
+
+type League struct {
+	Area Area   `json:"area"`
+	ID   int64  `json:"id"`
+	Name string `json:"name"`
+	Code string `json:"code"`
+	Type string `json:"type"`
+}
+
+// FootballAPIClient is the behavior contract that every implementation must
+// comply. It offers access to football-data.org data with handy methods. It is
+// NOT a full client implementation but access to required resources.
+type FootballAPIClient interface {
+
+	// GetLeagueByCode retrieves league data by its code.
+	GetLeagueByCode(code string) (*League, error)
+}
+
+// NewFootballAPIClient creates a new instance of real API client.
+func NewFootballAPIClient(apiKey string) FootballAPIClient {
+	if apiKey == "" {
+		panic("cannot work without a key")
+	}
+	return &realAPIClient{
+		baseURL: BASE_API_URL,
+		client: &http.Client{
+			Timeout: time.Second,
+		},
+		apiKey: apiKey,
+	}
+}
+
+type realAPIClient struct {
+	baseURL string
+	client  *http.Client
+	apiKey  string
+}
+
+func (r *realAPIClient) GetLeagueByCode(code string) (*League, error) {
+	url := r.baseURL + "/competitions/" + code
+
+	request, _ := http.NewRequest(http.MethodGet, url, nil)
+	request.Header.Set("X-Auth-Token", r.apiKey)
+
+	response, err := r.client.Do(request)
+	if err != nil {
+		return nil, err
+	}
+
+	var body []byte
+	defer response.Body.Close()
+	body, err = io.ReadAll(response.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if response.StatusCode != 200 {
+		return nil, errors.New("failed to retrieve content: " + string(body))
+	}
+
+	league := League{}
+	err = json.Unmarshal(body, &league)
+	if err != nil {
+		return nil, err
+	}
+	return &league, nil
+}

pkg/clients/football_test.go

@@ -0,0 +1,86 @@
+package clients
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewFootballAPIClient(t *testing.T) {
+	t.Run("fails without api key", func(t *testing.T) {
+		defer func() {
+			if r := recover(); r == nil {
+				t.Errorf("The code did not panic")
+			}
+		}()
+		NewFootballAPIClient("")
+	})
+
+	t.Run("ok", func(t *testing.T) {
+		NewFootballAPIClient("abc123")
+	})
+}
+
+func TestGetLeagueByCode(t *testing.T) {
+	testCases := []struct {
+		name       string
+		code       string
+		statusCode int
+		isSuccess  bool
+	}{
+		{"ok", "PL", 200, true},
+		{"not found", "XXX", 404, false},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			apiContent := loadGoldenFile(t.Name())
+			server := newTestServer("/competitions/"+tc.code, tc.statusCode, apiContent)
+			defer server.Close()
+
+			c := &realAPIClient{
+				baseURL: server.URL,
+				client: &http.Client{
+					Timeout: time.Second,
+				},
+				apiKey: "abc123",
+			}
+			response, err := c.GetLeagueByCode(tc.code)
+			assert.Equal(t, err == nil, tc.isSuccess)
+			assert.Equal(t, response != nil, tc.isSuccess)
+
+			if tc.isSuccess {
+				assert.Equal(t, "Premier League", response.Name)
+				assert.Equal(t, "PL", response.Code)
+				assert.Equal(t, "England", response.Area.Name)
+			} else {
+				assert.True(t, strings.Contains(err.Error(), "failed to retrieve content:"))
+			}
+		})
+	}
+}
+
+// loadGoldenFiles uses the test name to load a JSON value as expected result.
+func loadGoldenFile(testName string) []byte {
+	testName = strings.ReplaceAll(testName, " ", "_")
+	content, err := os.ReadFile("./golden/" + testName + ".json")
+	if err != nil {
+		panic(err)
+	}
+	return content
+}
+
+func newTestServer(url string, statusCode int, responseBody []byte) *httptest.Server {
+	mux := http.NewServeMux()
+	mux.HandleFunc(url, func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(statusCode)
+		w.Header().Set("Content-Type", "application/json")
+		w.Write(responseBody)
+	})
+	return httptest.NewServer(mux)
+}

pkg/clients/golden/TestGetLeagueByCode/not_found.json

@@ -0,0 +1,4 @@
+{
+  "message": "The resource you are looking for does not exist.",
+  "error": 404
+}