add checks

lib/random/random.go

@@ -226,7 +226,12 @@ func shuffle(thread *starlark.Thread, bn *starlark.Builtin, args starlark.Tuple,
 }
 
 // random() returns a random floating point number in the range 0.0 <= X < 1.0.
-func random(thread *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
+func random(thread *starlark.Thread, b *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
+	// check the arguments: no arguments
+	if err := starlark.UnpackPositionalArgs(b.Name(), args, kwargs, 0); err != nil {
+		return nil, err
+	}
+	// get random float
 	f, err := getRandomFloat(1 << 53)
 	if err != nil {
 		return nil, err
@@ -235,7 +240,12 @@ func random(thread *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, k
 }
 
 // uuid() returns a random UUID (RFC 4122 version 4).
-func uuid(thread *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
+func uuid(thread *starlark.Thread, b *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
+	// check the arguments: no arguments
+	if err := starlark.UnpackPositionalArgs(b.Name(), args, kwargs, 0); err != nil {
+		return nil, err
+	}
+	// get random UUID
 	u := guuid.New()
 	return starlark.String(u.String()), nil
 }
@@ -257,6 +267,8 @@ func uniform(thread *starlark.Thread, bn *starlark.Builtin, args starlark.Tuple,
 	return starlark.Float(float64(a) + diff*f), nil
 }
 
+// the following functions are not exposed to Starlark directly, but can be used in other Starlark builtins.
+
 // getRandomInt returns a random integer in the range [0, max).
 func getRandomInt(max int) (int, error) {
 	if max <= 0 {

lib/random/random_test.go

@@ -337,6 +337,14 @@ func TestLoadModule_Random(t *testing.T) {
 				return f >= 0 && f < 1
 			},
 		},
+		{
+			name: "random with invalid args",
+			script: itn.HereDoc(`
+				load('random', 'random')
+				random(1)
+			`),
+			wantErr: `random.random: got 1 arguments, want 0`,
+		},
 		{
 			name: "uniform with less than 2 args",
 			script: itn.HereDoc(`
@@ -415,6 +423,14 @@ func TestLoadModule_Random(t *testing.T) {
 				assert.eq(len(val.replace("-", "")), 32)
 			`),
 		},
+		{
+			name: "uuid with invalid args",
+			script: itn.HereDoc(`
+				load('random', 'uuid')
+				uuid(2)
+			`),
+			wantErr: `random.uuid: got 1 arguments, want 0`,
+		},
 		{
 			name: "randb32 with 0 or 1 args",
 			script: itn.HereDoc(`

lib/runtime/runtime.go

@@ -58,5 +58,8 @@ var (
 
 // getUpTime returns time elapsed since the app started.
 func getUpTime(thread *starlark.Thread, b *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
+	if err := starlark.UnpackPositionalArgs(b.Name(), args, kwargs, 0); err != nil {
+		return nil, err
+	}
 	return stdtime.Duration(time.Since(appStart)), nil
 }

lib/runtime/runtime_test.go

@@ -41,6 +41,14 @@ func TestLoadModule_Runtime(t *testing.T) {
 				print(s, u)
 			`),
 		},
+		{
+			name: `uptime invalid`,
+			script: itn.HereDoc(`
+				load('runtime', 'uptime')
+				uptime(123)
+			`),
+			wantErr: `runtime.uptime: got 1 arguments, want 0`,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {