test(mcp): add connect-timeout default behaviour tests

Add four tests in package mcp covering the connectTimeout defaulting logic
in NewHTTPConnection:

- TestNewHTTPConnection_DefaultConnectTimeout_ZeroInput
  Ensures that connectTimeout=0 falls back to defaultConnectTimeout (30 s).

- TestNewHTTPConnection_DefaultConnectTimeout_NegativeInput
  Ensures that connectTimeout<0 also falls back (guards the <= 0 fix for
  the bug identified in #3933).

- TestNewHTTPConnection_DefaultConnectTimeout_CustomValue
  Ensures that a positive connectTimeout is stored unchanged.

- TestDefaultConnectTimeout_Value
  Guards the constant value so any drift from config.DefaultConnectTimeout
  (30 s) causes an immediate, obvious test failure rather than a silent bug.

These tests directly exercise the paths fixed in fix(mcp):#3933 and
provide regression coverage for future changes.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

internal/mcp/connect_timeout_test.go

@@ -0,0 +1,87 @@
+package mcp
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// newMinimalTestServer returns an httptest server that responds with a minimal
+// JSON-RPC initialize result so NewHTTPConnection can complete its handshake.
+func newMinimalTestServer(t *testing.T) *httptest.Server {
+	t.Helper()
+	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		resp := map[string]interface{}{
+			"jsonrpc": "2.0",
+			"id":      1,
+			"result": map[string]interface{}{
+				"protocolVersion": "2024-11-05",
+				"serverInfo":      map[string]interface{}{"name": "test"},
+			},
+		}
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(resp) //nolint:errcheck
+	}))
+}
+
+// TestNewHTTPConnection_DefaultConnectTimeout_ZeroInput verifies that a zero
+// connectTimeout is replaced with defaultConnectTimeout (30 s).
+func TestNewHTTPConnection_DefaultConnectTimeout_ZeroInput(t *testing.T) {
+	srv := newMinimalTestServer(t)
+	defer srv.Close()
+
+	conn, err := NewHTTPConnection(context.Background(), "test", srv.URL,
+		map[string]string{"Authorization": "test"}, nil, "", 0, 0)
+	require.NoError(t, err)
+	require.NotNil(t, conn)
+	defer conn.Close()
+
+	assert.Equal(t, defaultConnectTimeout, conn.connectTimeout,
+		"zero connectTimeout should be replaced with defaultConnectTimeout")
+}
+
+// TestNewHTTPConnection_DefaultConnectTimeout_NegativeInput verifies that a
+// negative connectTimeout is also replaced with defaultConnectTimeout.
+func TestNewHTTPConnection_DefaultConnectTimeout_NegativeInput(t *testing.T) {
+	srv := newMinimalTestServer(t)
+	defer srv.Close()
+
+	conn, err := NewHTTPConnection(context.Background(), "test", srv.URL,
+		map[string]string{"Authorization": "test"}, nil, "", 0, -1*time.Second)
+	require.NoError(t, err)
+	require.NotNil(t, conn)
+	defer conn.Close()
+
+	assert.Equal(t, defaultConnectTimeout, conn.connectTimeout,
+		"negative connectTimeout should be replaced with defaultConnectTimeout")
+}
+
+// TestNewHTTPConnection_DefaultConnectTimeout_CustomValue verifies that a
+// positive connectTimeout is stored as-is without being replaced.
+func TestNewHTTPConnection_DefaultConnectTimeout_CustomValue(t *testing.T) {
+	srv := newMinimalTestServer(t)
+	defer srv.Close()
+
+	custom := 10 * time.Second
+	conn, err := NewHTTPConnection(context.Background(), "test", srv.URL,
+		map[string]string{"Authorization": "test"}, nil, "", 0, custom)
+	require.NoError(t, err)
+	require.NotNil(t, conn)
+	defer conn.Close()
+
+	assert.Equal(t, custom, conn.connectTimeout,
+		"a positive connectTimeout should be stored unchanged")
+}
+
+// TestDefaultConnectTimeout_Value guards against the constant value drifting
+// away from config.DefaultConnectTimeout (30 s) unintentionally.
+func TestDefaultConnectTimeout_Value(t *testing.T) {
+	assert.Equal(t, 30*time.Second, defaultConnectTimeout,
+		"defaultConnectTimeout must remain 30 s to stay in sync with config.DefaultConnectTimeout")
+}