test: add tests for mcp_base_url config and URL fallback priority

Author: ogabrielluiz

src/backend/tests/unit/api/v1/test_endpoints.py

@@ -291,3 +291,41 @@ async def test_get_config_authenticated_returns_full_config(client: AsyncClient,
     assert "auto_saving_interval" in result, "Authenticated response must contain 'auto_saving_interval'"
     assert "health_check_max_retries" in result, "Authenticated response must contain 'health_check_max_retries'"
     assert "feature_flags" in result, "Authenticated response must contain 'feature_flags'"
+
+
+async def test_get_config_returns_mcp_base_url(client: AsyncClient, logged_in_headers: dict):
+    """Test that /config includes mcp_base_url for both authenticated and unauthenticated responses."""
+    # Authenticated
+    response = await client.get("api/v1/config", headers=logged_in_headers)
+    result = response.json()
+    assert response.status_code == status.HTTP_200_OK
+    assert "mcp_base_url" in result, "Authenticated response must contain 'mcp_base_url'"
+    assert isinstance(result["mcp_base_url"], str), "mcp_base_url must be a string"
+
+    # Unauthenticated
+    response = await client.get("api/v1/config")
+    result = response.json()
+    assert response.status_code == status.HTTP_200_OK
+    assert "mcp_base_url" in result, "Public response must contain 'mcp_base_url'"
+    assert isinstance(result["mcp_base_url"], str), "mcp_base_url must be a string"
+
+
+async def test_get_config_mcp_base_url_defaults_to_empty(client: AsyncClient, logged_in_headers: dict):
+    """Test that mcp_base_url defaults to empty string when LANGFLOW_MCP_BASE_URL is not set."""
+    response = await client.get("api/v1/config", headers=logged_in_headers)
+    result = response.json()
+    assert response.status_code == status.HTTP_200_OK
+    assert result["mcp_base_url"] == ""
+
+
+async def test_get_config_mcp_base_url_from_settings(client: AsyncClient, logged_in_headers: dict, monkeypatch):
+    """Test that mcp_base_url reflects the value from settings."""
+    from langflow.services.deps import get_settings_service
+
+    settings_service = get_settings_service()
+    monkeypatch.setattr(settings_service.settings, "mcp_base_url", "https://langflow.example.com")
+
+    response = await client.get("api/v1/config", headers=logged_in_headers)
+    result = response.json()
+    assert response.status_code == status.HTTP_200_OK
+    assert result["mcp_base_url"] == "https://langflow.example.com"

src/frontend/src/customization/utils/__tests__/custom-mcp-url.test.ts

@@ -0,0 +1,99 @@
+import { api } from "@/controllers/API/api";
+import { useUtilityStore } from "@/stores/utilityStore";
+import { customGetMCPUrl } from "../custom-mcp-url";
+
+describe("customGetMCPUrl", () => {
+  const originalBaseURL = api.defaults.baseURL;
+
+  afterEach(() => {
+    api.defaults.baseURL = originalBaseURL;
+    useUtilityStore.setState({ mcpBaseUrl: "" });
+  });
+
+  it("uses mcpBaseUrl from store when set", () => {
+    api.defaults.baseURL = "";
+    useUtilityStore.setState({ mcpBaseUrl: "https://custom.example.com" });
+
+    const url = customGetMCPUrl("proj-1");
+
+    expect(url).toBe(
+      "https://custom.example.com/api/v1/mcp/project/proj-1/streamable",
+    );
+  });
+
+  it("mcpBaseUrl takes priority over api.defaults.baseURL", () => {
+    api.defaults.baseURL = "https://api-default.example.com";
+    useUtilityStore.setState({ mcpBaseUrl: "https://override.example.com" });
+
+    const url = customGetMCPUrl("proj-1");
+
+    expect(url).toBe(
+      "https://override.example.com/api/v1/mcp/project/proj-1/streamable",
+    );
+  });
+
+  it("falls back to api.defaults.baseURL when mcpBaseUrl is empty", () => {
+    api.defaults.baseURL = "https://api-default.example.com";
+    useUtilityStore.setState({ mcpBaseUrl: "" });
+
+    const url = customGetMCPUrl("proj-1");
+
+    expect(url).toBe(
+      "https://api-default.example.com/api/v1/mcp/project/proj-1/streamable",
+    );
+  });
+
+  it("falls back to window.location.origin when both are empty", () => {
+    api.defaults.baseURL = "";
+    useUtilityStore.setState({ mcpBaseUrl: "" });
+
+    const url = customGetMCPUrl("proj-1");
+
+    expect(url).toBe(
+      `${window.location.origin}/api/v1/mcp/project/proj-1/streamable`,
+    );
+  });
+
+  it("strips trailing slashes from mcpBaseUrl", () => {
+    useUtilityStore.setState({ mcpBaseUrl: "https://example.com/" });
+
+    const url = customGetMCPUrl("proj-1");
+
+    expect(url).toBe(
+      "https://example.com/api/v1/mcp/project/proj-1/streamable",
+    );
+  });
+
+  it("strips multiple trailing slashes", () => {
+    useUtilityStore.setState({ mcpBaseUrl: "https://example.com///" });
+
+    const url = customGetMCPUrl("proj-1");
+
+    expect(url).toBe(
+      "https://example.com/api/v1/mcp/project/proj-1/streamable",
+    );
+  });
+
+  it("returns SSE URL when transport is sse", () => {
+    useUtilityStore.setState({ mcpBaseUrl: "https://example.com" });
+
+    const url = customGetMCPUrl("proj-1", {}, "sse");
+
+    expect(url).toBe("https://example.com/api/v1/mcp/project/proj-1/sse");
+  });
+
+  it("returns composer URL when useComposer is true and streamableHttpUrl is set", () => {
+    useUtilityStore.setState({ mcpBaseUrl: "https://should-not-use.com" });
+
+    const url = customGetMCPUrl(
+      "proj-1",
+      {
+        useComposer: true,
+        streamableHttpUrl: "https://composer.example.com/streamable",
+      },
+      "streamablehttp",
+    );
+
+    expect(url).toBe("https://composer.example.com/streamable");
+  });
+});