Skip Go session-resume E2E tests on in-process macOS

Resuming a session over the in-process transport under CLI 1.0.81-2 no
longer routes model traffic through COPILOT_API_URL, so the CLI reaches
the real api.githubcopilot.com and macOS rejects the proxy certificate
with an EKU error. Coverage is retained over stdio on every OS and
in-process on Linux and Windows.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 812b44f2-ef93-4b32-b051-c7092f612279

Author: stephentoub

go/internal/e2e/session_e2e_test.go

@@ -448,6 +448,10 @@ func TestSessionE2E(t *testing.T) {
 	})
 
 	t.Run("should resume a session using a new client", func(t *testing.T) {
+		// TODO(cli-1.0.81-2): resuming a session over the in-process transport no longer
+		// routes model traffic through COPILOT_API_URL, so the CLI reaches the real
+		// api.githubcopilot.com and macOS rejects the proxy certificate with an EKU error.
+		testharness.SkipIfInProcessOnMacOS(t, "session resume ignores COPILOT_API_URL")
 		ctx.ConfigureForTest(t)
 
 		// Create initial session

go/internal/e2e/streaming_fidelity_e2e_test.go

@@ -142,6 +142,10 @@ func TestStreamingFidelityE2E(t *testing.T) {
 	})
 
 	t.Run("should produce deltas after session resume", func(t *testing.T) {
+		// TODO(cli-1.0.81-2): resuming a session over the in-process transport no longer
+		// routes model traffic through COPILOT_API_URL, so the CLI reaches the real
+		// api.githubcopilot.com and macOS rejects the proxy certificate with an EKU error.
+		testharness.SkipIfInProcessOnMacOS(t, "session resume ignores COPILOT_API_URL")
 		ctx.ConfigureForTest(t)
 
 		session, err := client.CreateSession(t.Context(), &copilot.SessionConfig{
@@ -212,6 +216,10 @@ func TestStreamingFidelityE2E(t *testing.T) {
 	})
 
 	t.Run("should not produce deltas after session resume with streaming disabled", func(t *testing.T) {
+		// TODO(cli-1.0.81-2): resuming a session over the in-process transport no longer
+		// routes model traffic through COPILOT_API_URL, so the CLI reaches the real
+		// api.githubcopilot.com and macOS rejects the proxy certificate with an EKU error.
+		testharness.SkipIfInProcessOnMacOS(t, "session resume ignores COPILOT_API_URL")
 		ctx.ConfigureForTest(t)
 
 		session, err := client.CreateSession(t.Context(), &copilot.SessionConfig{

go/internal/e2e/testharness/context.go

@@ -114,6 +114,16 @@ func SkipIfInProcess(t *testing.T, reason string) {
 	}
 }
 
+// SkipIfInProcessOnMacOS skips the test when E2E tests run under the in-process
+// (FFI) transport on macOS. Coverage is retained over stdio on every OS and
+// in-process on Linux and Windows.
+func SkipIfInProcessOnMacOS(t *testing.T, reason string) {
+	t.Helper()
+	if isInProcessTransport() && runtime.GOOS == "darwin" {
+		t.Skipf("unsupported over the in-process (FFI) transport on macOS: %s", reason)
+	}
+}
+
 // NewTestContext creates a new test context with isolated directories and a replaying proxy.
 func NewTestContext(t *testing.T) *TestContext {
 	t.Helper()