test(backend): add unit tests for auth_middleware, fortee, processor, account, and more handlers

Cover previously untested code: SessionCookieMiddleware, context helpers,
downloadFile, addAcceptHeader, doProcessTaskRunTestcase, updateSubmissionAndGameState,
PostLogout, GetGames, PostGamePlayCode, GetGameWatchRanking, GetGameWatchLatestStates.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/backend/fortee/fortee_test.go b/backend/fortee/fortee_test.go
new file mode 100644
index 0000000..90ae625
--- /dev/null
+++ b/backend/fortee/fortee_test.go
@@ -0,0 +1,44 @@
+package fortee
+
+import (
+	"context"
+	"net/http"
+	"testing"
+)
+
+func TestAddAcceptHeader(t *testing.T) {
+	req, err := http.NewRequest(http.MethodGet, "https://example.com", nil)
+	if err != nil {
+		t.Fatalf("failed to create request: %v", err)
+	}
+
+	if err := addAcceptHeader(context.Background(), req); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	got := req.Header.Get("Accept")
+	if got != "application/json" {
+		t.Errorf("expected Accept header 'application/json', got %q", got)
+	}
+}
+
+func TestEndpoint(t *testing.T) {
+	if Endpoint != "https://fortee.jp" {
+		t.Errorf("expected endpoint 'https://fortee.jp', got %q", Endpoint)
+	}
+}
+
+func TestErrorValues(t *testing.T) {
+	if ErrLoginFailed == nil {
+		t.Error("ErrLoginFailed should not be nil")
+	}
+	if ErrUserNotFound == nil {
+		t.Error("ErrUserNotFound should not be nil")
+	}
+	if ErrLoginFailed.Error() != "fortee login failed" {
+		t.Errorf("unexpected error message: %q", ErrLoginFailed.Error())
+	}
+	if ErrUserNotFound.Error() != "fortee user not found" {
+		t.Errorf("unexpected error message: %q", ErrUserNotFound.Error())
+	}
+}