test: add pkg tests for gemini, openai, geminicli packages

- Add sanitize tests (internal/pkg/geminicli): 55.3%
- Add constants/model tests (internal/pkg/openai): 34.2%
- Add models tests (internal/pkg/gemini): 100%

internal/pkg/openai/constants_test.go

@@ -0,0 +1,49 @@
+package openai
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestDefaultModelIDs(t *testing.T) {
+	ids := DefaultModelIDs()
+	
+	// Should return same number of IDs as DefaultModels
+	require.Equal(t, len(DefaultModels), len(ids))
+	
+	// Check all expected IDs are present
+	expected := []string{
+		"gpt-5.4",
+		"gpt-5.4-mini",
+		"gpt-5.4-nano",
+		"gpt-5.3-codex",
+		"gpt-5.3-codex-spark",
+		"gpt-5.2",
+		"gpt-5.2-codex",
+		"gpt-5.1-codex-max",
+		"gpt-5.1-codex",
+		"gpt-5.1",
+		"gpt-5.1-codex-mini",
+		"gpt-5",
+	}
+	require.Equal(t, expected, ids)
+}
+
+func TestDefaultModels(t *testing.T) {
+	// Verify DefaultModels is not empty
+	require.NotEmpty(t, DefaultModels)
+	
+	// Verify each model has required fields
+	for _, m := range DefaultModels {
+		require.NotEmpty(t, m.ID, "Model ID should not be empty")
+		require.NotEmpty(t, m.DisplayName, "DisplayName should not be empty")
+		require.NotEmpty(t, m.Object, "Object should not be empty")
+		require.NotEmpty(t, m.OwnedBy, "OwnedBy should not be empty")
+		require.NotZero(t, m.Created, "Created should not be zero")
+	}
+}
+
+func TestDefaultTestModel(t *testing.T) {
+	require.Equal(t, "gpt-5.1-codex", DefaultTestModel)
+}