internal/shader: refactoring

internal/shader/syntax_test.go

@@ -1202,39 +1202,31 @@ func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
 }
 
 func TestSyntaxAtan(t *testing.T) {
-	// `atan` takes 1 argument.
-	if _, err := compileToIR([]byte(`package main
+	cases := []struct {
+		stmt string
+		err  bool
+	}{
+		// `atan` takes 1 argument.
+		{stmt: "_ = atan(vec4(0))", err: false},
+		{stmt: "_ = atan(vec4(0), vec4(0))", err: true},
 
-func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
-	return atan(vec4(0))
-}
-`)); err != nil {
-		t.Error(err)
+		// `atan2` takes 2 arguments.
+		{stmt: "_ = atan2(vec4(0))", err: true},
+		{stmt: "_ = atan2(vec4(0), vec4(0))", err: false},
 	}
-	if _, err := compileToIR([]byte(`package main
+
+	for _, c := range cases {
+		_, err := compileToIR([]byte(fmt.Sprintf(`package main
 
 func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
-	return atan(vec4(0), vec4(0))
-}
-`)); err == nil {
-		t.Errorf("error must be non-nil but was nil")
-	}
-	// `atan2` takes 2 arguments.
-	if _, err := compileToIR([]byte(`package main
-
-func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
-	return atan2(vec4(0))
-}
-`)); err == nil {
-		t.Errorf("error must be non-nil but was nil")
-	}
-	if _, err := compileToIR([]byte(`package main
-
-func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
-	return atan2(vec4(0), vec4(0))
-}
-`)); err != nil {
-		t.Error(err)
+	%s
+	return position
+}`, c.stmt)))
+		if err == nil && c.err {
+			t.Errorf("%s must return an error but does not", c.stmt)
+		} else if err != nil && !c.err {
+			t.Errorf("%s must not return nil but returned %v", c.stmt, err)
+		}
 	}
 }