From a71baa49cdf7989073a2c32ba1d841e80850102a Mon Sep 17 00:00:00 2001
From: Tomas Dvorak <contact.dvorak@gmail.com>
Date: Thu, 24 Sep 2026 22:58:55 +0200
Subject: [PATCH] test: regression coverage for error mapping and client error
 extraction
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- handlers: pgx.ErrNoRows→404, InputError→400 with message preserved,
  pgconn 23505→409 without constraint/SQLSTATE leak, unknown→500
- services: export NewInputError so error construction is testable
- frontend: vitest for errorMessage helper — server reason preferred,
  status text and fallbacks verified

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
---
 apps/backend/internal/handlers/http_test.go   | 47 +++++++++++++++++++
 .../internal/services/platform_service.go     |  2 +
 .../src/lib/__tests__/errorMessage.test.ts    | 29 ++++++++++++
 3 files changed, 78 insertions(+)
 create mode 100644 apps/frontend/src/lib/__tests__/errorMessage.test.ts

diff --git a/apps/backend/internal/handlers/http_test.go b/apps/backend/internal/handlers/http_test.go
index 8e44012..7cbc865 100644
--- a/apps/backend/internal/handlers/http_test.go
+++ b/apps/backend/internal/handlers/http_test.go
@@ -4,9 +4,14 @@ import (
 	"errors"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
 
 	"github.com/gin-gonic/gin"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
+
+	"github.com/tdvorak/primora/apps/backend/internal/services"
 )
 
 func newTestContext(rawQuery string) (*gin.Context, *httptest.ResponseRecorder) {
@@ -104,4 +109,46 @@ func TestHandleErrorStatusMapping(t *testing.T) {
 			t.Fatalf("unexpected status: %d", recorder.Code)
 		}
 	})
+
+	t.Run("maps missing rows to not found", func(t *testing.T) {
+		t.Parallel()
+		ctx, recorder := newTestContext("")
+		handler.handleError(ctx, pgx.ErrNoRows)
+		if recorder.Code != http.StatusNotFound {
+			t.Fatalf("unexpected status: %d", recorder.Code)
+		}
+	})
+
+	t.Run("maps InputError to bad request with message", func(t *testing.T) {
+		t.Parallel()
+		ctx, recorder := newTestContext("")
+		handler.handleError(ctx, services.NewInputError("webhook url must be https"))
+		if recorder.Code != http.StatusBadRequest {
+			t.Fatalf("unexpected status: %d", recorder.Code)
+		}
+		if !strings.Contains(recorder.Body.String(), "webhook url must be https") {
+			t.Fatalf("expected reason in body, got %s", recorder.Body.String())
+		}
+	})
+
+	t.Run("maps unique violation to conflict without leaking", func(t *testing.T) {
+		t.Parallel()
+		ctx, recorder := newTestContext("")
+		handler.handleError(ctx, &pgconn.PgError{Code: "23505", Message: "duplicate key value violates unique constraint \"projects_slug_key\""})
+		if recorder.Code != http.StatusConflict {
+			t.Fatalf("unexpected status: %d", recorder.Code)
+		}
+		if strings.Contains(recorder.Body.String(), "projects_slug_key") || strings.Contains(recorder.Body.String(), "23505") {
+			t.Fatalf("raw constraint leaked: %s", recorder.Body.String())
+		}
+	})
+
+	t.Run("maps unknown pg error to internal error", func(t *testing.T) {
+		t.Parallel()
+		ctx, recorder := newTestContext("")
+		handler.handleError(ctx, &pgconn.PgError{Code: "XX000", Message: "internal"})
+		if recorder.Code != http.StatusInternalServerError {
+			t.Fatalf("unexpected status: %d", recorder.Code)
+		}
+	})
 }
diff --git a/apps/backend/internal/services/platform_service.go b/apps/backend/internal/services/platform_service.go
index 41f3c79..979c700 100644
--- a/apps/backend/internal/services/platform_service.go
+++ b/apps/backend/internal/services/platform_service.go
@@ -1534,6 +1534,8 @@ type InputError struct{ msg string }
 
 func (e *InputError) Error() string { return e.msg }
 
+func NewInputError(msg string) error { return &InputError{msg: msg} }
+
 func inputErrorf(format string, args ...any) error {
 	return &InputError{msg: fmt.Sprintf(format, args...)}
 }
diff --git a/apps/frontend/src/lib/__tests__/errorMessage.test.ts b/apps/frontend/src/lib/__tests__/errorMessage.test.ts
new file mode 100644
index 0000000..0b7b50f
--- /dev/null
+++ b/apps/frontend/src/lib/__tests__/errorMessage.test.ts
@@ -0,0 +1,29 @@
+import { describe, expect, it } from "vitest";
+
+import { errorMessage } from "../api";
+
+describe("errorMessage", () => {
+  it("prefers the server's reason over the HTTP status text", () => {
+    const apiError = {
+      message: "Bad Request",
+      body: { error: { message: "webhook url must be https (http allowed only for private/self-hosted targets)" } },
+    };
+    expect(errorMessage(apiError)).toBe(
+      "webhook url must be https (http allowed only for private/self-hosted targets)",
+    );
+  });
+
+  it("falls back to error.message when no body reason exists", () => {
+    expect(errorMessage(new Error("network down"))).toBe("network down");
+  });
+
+  it("uses the fallback for non-error values", () => {
+    expect(errorMessage(null, "Nope")).toBe("Nope");
+    expect(errorMessage(undefined)).toBe("Request failed");
+    expect(errorMessage("string failure")).toBe("Request failed");
+  });
+
+  it("ignores empty body and message strings", () => {
+    expect(errorMessage({ message: "", body: { error: { message: "" } } }, "Empty")).toBe("Empty");
+  });
+});