chore: update test

pkg/agent/context_test.go

@@ -22,7 +22,6 @@ func TestBuildMessages_CoalescesConsecutiveUserMessages(t *testing.T) {
 		cb := NewContextBuilder(ws)
 
 		history := []providers.Message{
-			{Role: "system", Content: "sys"},
 			{Role: "assistant", Content: "hi"},
 			{Role: "user", Content: "first"},
 		}
@@ -31,16 +30,28 @@ func TestBuildMessages_CoalescesConsecutiveUserMessages(t *testing.T) {
 		if len(msgs) < 2 {
 			t.Fatalf("expected at least 2 messages, got %d", len(msgs))
 		}
+		// BuildMessages should inject a single fresh system message at the start
 		if msgs[0].Role != "system" {
 			t.Fatalf("expected first message to be system, got %s", msgs[0].Role)
 		}
-		// ensure no consecutive user messages and last is a single coalesced user
+		for i := 1; i < len(msgs); i++ {
+			if msgs[i].Role == "system" {
+				t.Fatalf("unexpected system message at index %d; history should not include system messages", i)
+			}
+		}
+		// ensure no two consecutive messages are from user anywhere in the list
+		for i := 1; i < len(msgs); i++ {
+			if msgs[i-1].Role == "user" && msgs[i].Role == "user" {
+				t.Fatalf("found consecutive user messages at indices %d and %d", i-1, i)
+			}
+		}
+		// and the last is a single coalesced user message
 		last := msgs[len(msgs)-1]
 		if last.Role != "user" {
 			t.Fatalf("expected last message role=user, got %s", last.Role)
 		}
-		if last.Content != "first\n\nsecond" {
+		if got, want := last.Content, "first\n\nsecond"; got != want {
-			t.Fatalf("expected coalesced content 'first\\n\\nsecond', got %q", last.Content)
+			t.Fatalf("expected coalesced content %q, got %q", want, got)
 		}
 	})
 }
@@ -63,3 +74,39 @@ func TestBuildMessages_AppendsUserIfNoConsecutive(t *testing.T) {
 		}
 	})
 }
+
+func TestBuildMessages_CoalescesWithEmptyLastUserMessage(t *testing.T) {
+	withTempWorkspace(t, func(ws string) {
+		cb := NewContextBuilder(ws)
+		history := []providers.Message{
+			{Role: "assistant", Content: "hi"},
+			{Role: "user", Content: ""},
+		}
+		msgs := cb.BuildMessages(history, "", "second", nil, "cli", "chat1")
+		if len(msgs) < 2 {
+			t.Fatalf("expected at least 2 messages, got %d", len(msgs))
+		}
+		// Only one injected system message should be at index 0
+		if msgs[0].Role != "system" {
+			t.Fatalf("expected first message to be system, got %s", msgs[0].Role)
+		}
+		for i := 1; i < len(msgs); i++ {
+			if msgs[i].Role == "system" {
+				t.Fatalf("unexpected system message at index %d; history should not include system messages", i)
+			}
+		}
+		// ensure no consecutive user messages anywhere
+		for i := 1; i < len(msgs); i++ {
+			if msgs[i-1].Role == "user" && msgs[i].Role == "user" {
+				t.Fatalf("found consecutive user messages at indices %d and %d", i-1, i)
+			}
+		}
+		last := msgs[len(msgs)-1]
+		if last.Role != "user" {
+			t.Fatalf("expected last message role=user, got %s", last.Role)
+		}
+		if last.Content != "second" {
+			t.Fatalf("expected coalesced content 'second' when last history content is empty, got %q", last.Content)
+		}
+	})
+}