test: Add coverage for healthcheck server

internal/http/healthcheck_server_test.go

@@ -0,0 +1,166 @@
+package http
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"testing"
+)
+
+func TestHealthCheckHandler(t *testing.T) {
+	tests := []struct {
+		name           string
+		method         string
+		expectedStatus int
+		wantBody       bool
+	}{
+		{
+			name:           "GET request returns 200 and status ok",
+			method:         http.MethodGet,
+			expectedStatus: http.StatusOK,
+			wantBody:       true,
+		},
+		{
+			name:           "POST request returns 405 and status not allowed",
+			method:         http.MethodPost,
+			expectedStatus: http.StatusMethodNotAllowed,
+			wantBody:       false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req := httptest.NewRequest(tt.method, "/healthz", nil)
+			w := httptest.NewRecorder()
+
+			handleHealthCheck(w, req)
+
+			if got := w.Code; got != tt.expectedStatus {
+				t.Errorf("handleHealthCheck() status = %v, want %v", got, tt.expectedStatus)
+			}
+
+			if tt.wantBody {
+				var response struct {
+					Status string `json:"status"`
+				}
+
+				if err := json.NewDecoder(w.Body).Decode(&response); err != nil {
+					t.Errorf("failed to decode response body: %v", err)
+				}
+
+				if response.Status != "ok" {
+					t.Errorf("handleHealthCheck() status = %v, want %v", response.Status, "ok")
+				}
+
+				if contentType := w.Header().Get("Content-Type"); contentType != "application/json" {
+					t.Errorf("handleHealthCheck() Content-Type = %v, want %v", contentType, "application/json")
+				}
+			}
+		})
+	}
+}
+
+func TestHealthCheckHandlerEncodingError(t *testing.T) {
+	req := httptest.NewRequest(http.MethodGet, "/healthz", nil)
+
+	failingWriter := &failingWriter{
+		headers: http.Header{},
+	}
+	handleHealthCheck(failingWriter, req)
+
+	if failingWriter.statusCode != http.StatusInternalServerError {
+		t.Errorf("handleHealthCheck() with encoding error, status = %v, want %v",
+			failingWriter.statusCode, http.StatusInternalServerError)
+	}
+}
+
+type failingWriter struct {
+	statusCode int
+	headers    http.Header
+}
+
+func (w *failingWriter) Header() http.Header {
+	return w.headers
+}
+
+func (w *failingWriter) Write([]byte) (int, error) {
+	return 0, fmt.Errorf("encoding error")
+}
+
+func (w *failingWriter) WriteHeader(statusCode int) {
+	w.statusCode = statusCode
+}
+
+func TestNewHealthCheckServer(t *testing.T) {
+	server := NewHealthCheckServer()
+
+	if server == nil {
+		t.Fatal("NewHealthCheckServer() returned nil")
+		return
+	}
+
+	if server.Addr != ":5680" {
+		t.Errorf("NewHealthCheckServer() addr = %v, want %v", server.Addr, ":5680")
+	}
+
+	if server.ReadTimeout != readTimeout {
+		t.Errorf("NewHealthCheckServer() readTimeout = %v, want %v", server.ReadTimeout, readTimeout)
+	}
+
+	if server.WriteTimeout != writeTimeout {
+		t.Errorf("NewHealthCheckServer() writeTimeout = %v, want %v", server.WriteTimeout, writeTimeout)
+	}
+}
+
+func TestGetPort(t *testing.T) {
+	tests := []struct {
+		name         string
+		envPort      string
+		expectedPort int
+	}{
+		{
+			name:         "returns default port when env var is not set",
+			envPort:      "",
+			expectedPort: defaultPort,
+		},
+		{
+			name:         "returns custom port when valid env var is set",
+			envPort:      "8080",
+			expectedPort: 8080,
+		},
+		{
+			name:         "returns default port when env var is negative",
+			envPort:      "-1",
+			expectedPort: defaultPort,
+		},
+		{
+			name:         "returns default port when env var is zero",
+			envPort:      "0",
+			expectedPort: defaultPort,
+		},
+		{
+			name:         "returns default port when env var is too large",
+			envPort:      "65536",
+			expectedPort: defaultPort,
+		},
+		{
+			name:         "returns default port when env var is not a number",
+			envPort:      "invalid",
+			expectedPort: defaultPort,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			os.Setenv(portEnvVar, tt.envPort)
+
+			if got := GetPort(); got != tt.expectedPort {
+				t.Errorf("GetPort() = %v, want %v", got, tt.expectedPort)
+			}
+
+			os.Unsetenv(portEnvVar)
+		})
+	}
+}