diff --git a/funcs_test.go b/funcs_test.go
index 1c58e3e..7df2e82 100644
--- a/funcs_test.go
+++ b/funcs_test.go
@@ -68,6 +68,15 @@ func TestFuncs(t *testing.T) {
 		/*  55 */ {`builtin "math.arith"; add(1,2)`, int64(3), nil},
 		/*  56 */ {`fract("2.2(3)")`, newFraction(67, 30), nil},
 		/*  57 */ {`fract("1.21(3)")`, newFraction(91, 75), nil},
+		/*  58 */ {`fract(1.21(3))`, newFraction(91, 75), nil},
+		/*  59 */ {`fract(1.21)`, newFraction(121, 100), nil},
+		/*  60 */ {`dec(2)`, float64(2), nil},
+		/*  61 */ {`dec(2.0)`, float64(2), nil},
+		/*  62 */ {`dec("2.0")`, float64(2), nil},
+		/*  63 */ {`dec(true)`, float64(1), nil},
+		/*  64 */ {`dec(true")`, nil, errors.New("[1:11] missing string termination \"")},
+		/*  65 */ {`builtin "string"; joinStr("-", [1, "two", "three"])`, nil, errors.New(`joinStr() expected string, got int64 (1)`)},
+		// /*  64 */ {`string(true)`, "true", nil},
 	}
 
 	t.Setenv("EXPR_PATH", ".")