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/geminicli/sanitize_test.go

@@ -0,0 +1,103 @@
+package geminicli
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestIsBase64Char(t *testing.T) {
+	tests := []struct {
+		char byte
+		want bool
+	}{
+		{'A', true}, {'Z', true},
+		{'a', true}, {'z', true},
+		{'0', true}, {'9', true},
+		{'+', true}, {'/', true}, {'=', true},
+		{'-', false}, {'_', false}, {' ', false},
+		{'.', false}, {'\n', false},
+	}
+
+	for _, tt := range tests {
+		t.Run(string(tt.char), func(t *testing.T) {
+			got := isBase64Char(tt.char)
+			require.Equal(t, tt.want, got)
+		})
+	}
+}
+
+func TestTruncateBase64InMessage(t *testing.T) {
+	tests := []struct {
+		name string
+		msg  string
+		want string
+	}{
+		{
+			name: "no_base64",
+			msg:  "This is a normal message without base64",
+			want: "This is a normal message without base64",
+		},
+		{
+			name: "short_base64",
+			msg:  "data:image/png;base64,abc123",
+			want: "data:image/png;base64,abc123",
+		},
+		{
+			name: "long_base64_truncated",
+			msg:  "data:image/png;base64," + strings.Repeat("a", 100),
+			want: "data:image/png;base64," + strings.Repeat("a", 50) + "...[truncated]",
+		},
+		{
+			name: "multiple_base64",
+			msg:  "start;base64," + strings.Repeat("b", 30) + " middle;base64," + strings.Repeat("c", 60),
+			want: "start;base64," + strings.Repeat("b", 30) + " middle;base64," + strings.Repeat("c", 50) + "...[truncated]",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := truncateBase64InMessage(tt.msg)
+			require.Equal(t, tt.want, got)
+		})
+	}
+}
+
+func TestSanitizeBodyForLogs(t *testing.T) {
+	tests := []struct {
+		name string
+		body string
+		check func(t *testing.T, got string)
+	}{
+		{
+			name: "short_body_no_change",
+			body: "Short message",
+			check: func(t *testing.T, got string) {
+				require.Equal(t, "Short message", got)
+			},
+		},
+		{
+			name: "body_truncated",
+			body: strings.Repeat("x", 3000),
+			check: func(t *testing.T, got string) {
+				require.LessOrEqual(t, len(got), 2100) // maxLogBodyLen + "...[truncated]"
+				require.True(t, strings.HasSuffix(got, "...[truncated]"))
+			},
+		},
+		{
+			name: "body_with_base64_truncated",
+			body: "data:image/png;base64," + strings.Repeat("a", 100),
+			check: func(t *testing.T, got string) {
+				require.Contains(t, got, "...[truncated]")
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SanitizeBodyForLogs(tt.body)
+			tt.check(t, got)
+		})
+	}
+}