feat(zarinhub): automate access token refresh

backend/internal/zarinhub/client_test.go

@@ -97,7 +97,7 @@ func TestClientConvertSuccess(t *testing.T) {
 			Timeout: time.Second,
 		},
 		server.URL,
-		token,
+		&fakeTokenProvider{tokens: []string{token}},
 	)
 
 	result, err := client.Convert(
@@ -171,7 +171,7 @@ func TestClientReturnsRejectedForApplicationFailure(
 			Timeout: time.Second,
 		},
 		server.URL,
-		"test-token",
+		&fakeTokenProvider{tokens: []string{"test-token"}},
 	)
 
 	result, err := client.Convert(
@@ -263,7 +263,7 @@ func TestClientMapsHTTPStatusErrors(t *testing.T) {
 						Timeout: time.Second,
 					},
 					server.URL,
-					"test-token",
+					&fakeTokenProvider{tokens: []string{"test-token"}},
 				)
 
 				result, err := client.Convert(
@@ -321,7 +321,7 @@ func TestClientReturnsInvalidResponseForMalformedJSON(
 			Timeout: time.Second,
 		},
 		server.URL,
-		"test-token",
+		&fakeTokenProvider{tokens: []string{"test-token"}},
 	)
 
 	result, err := client.Convert(
@@ -366,7 +366,7 @@ func TestClientReturnsTimeout(t *testing.T) {
 			Timeout: 50 * time.Millisecond,
 		},
 		server.URL,
-		"test-token",
+		&fakeTokenProvider{tokens: []string{"test-token"}},
 	)
 
 	_, err := client.Convert(
@@ -402,7 +402,7 @@ func TestClientRejectsOversizedResponse(t *testing.T) {
 	client := NewClient(
 		&http.Client{Timeout: time.Second},
 		server.URL,
-		"test-token",
+		&fakeTokenProvider{tokens: []string{"test-token"}},
 	)
 
 	_, err := client.Convert(
@@ -414,3 +414,67 @@ func TestClientRejectsOversizedResponse(t *testing.T) {
 		t.Fatalf("error = %v, want ErrInvalidResponse", err)
 	}
 }
+
+func TestClientRefreshesAndRetriesUnauthorizedRequest(t *testing.T) {
+	const expectedIBAN = "IR820540102680020817909002"
+	requestCount := 0
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		requestCount++
+		authorization := r.Header.Get("Authorization")
+
+		if requestCount == 1 {
+			if authorization != "Bearer expired-token" {
+				t.Errorf("first authorization = %q", authorization)
+			}
+			w.WriteHeader(http.StatusUnauthorized)
+			return
+		}
+
+		if authorization != "Bearer fresh-token" {
+			t.Errorf("second authorization = %q", authorization)
+		}
+		fmt.Fprintf(w, `{
+			"data":{"iban":%q},
+			"meta":{"isSuccess":true,"errors":[]}
+		}`, expectedIBAN)
+	}))
+	defer server.Close()
+
+	tokens := &fakeTokenProvider{tokens: []string{"expired-token", "fresh-token"}}
+	client := NewClient(server.Client(), server.URL, tokens)
+
+	result, err := client.Convert(context.Background(), "6037997512345678")
+	if err != nil {
+		t.Fatalf("Convert() error = %v", err)
+	}
+	if result.IBAN != expectedIBAN {
+		t.Errorf("IBAN = %q, want %q", result.IBAN, expectedIBAN)
+	}
+	if requestCount != 2 {
+		t.Errorf("request count = %d, want 2", requestCount)
+	}
+	if len(tokens.invalidated) != 1 || tokens.invalidated[0] != "expired-token" {
+		t.Errorf("invalidated tokens = %v", tokens.invalidated)
+	}
+}
+
+type fakeTokenProvider struct {
+	tokens      []string
+	calls       int
+	invalidated []string
+}
+
+func (p *fakeTokenProvider) AccessToken(context.Context) (string, error) {
+	index := p.calls
+	if index >= len(p.tokens) {
+		index = len(p.tokens) - 1
+	}
+	p.calls++
+
+	return p.tokens[index], nil
+}
+
+func (p *fakeTokenProvider) Invalidate(token string) {
+	p.invalidated = append(p.invalidated, token)
+}