diff --git a/lib/utils/__tests__/isStandardSyntaxDeclaration.test.js b/lib/utils/__tests__/isStandardSyntaxDeclaration.test.js
index c0a3fc5978..bfc969d712 100644
--- a/lib/utils/__tests__/isStandardSyntaxDeclaration.test.js
+++ b/lib/utils/__tests__/isStandardSyntaxDeclaration.test.js
@@ -1,241 +1,179 @@
 'use strict';
 
 const isStandardSyntaxDeclaration = require('../isStandardSyntaxDeclaration');
-const less = require('postcss-less');
 const postcss = require('postcss');
-const sass = require('postcss-sass');
-const scss = require('postcss-scss');
+const postcssLess = require('postcss-less');
+const postcssSass = require('postcss-sass');
+const postcssScss = require('postcss-scss');
 
 describe('isStandardSyntaxDeclaration', () => {
 	it('standard prop and value', () => {
-		decls('a { a: b }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(decl('a { a: b }'))).toBe(true);
 	});
 
 	it('standard prop and scss var', () => {
-		decls('a { a: $b }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(decl('a { a: $b }'))).toBe(true);
 	});
 
 	it('custom-property', () => {
-		decls('a { --custom-property: x }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(decl('a { --custom-property: x }'))).toBe(true);
 	});
 
 	it('standard prop and calc value', () => {
-		decls('a { a : calc(b + c) }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(decl('a { a : calc(b + c) }'))).toBe(true);
 	});
 
 	it('does not break @selector', () => {
-		decls('@page { size: A4 }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(decl('@page { size: A4 }'))).toBe(true);
 	});
 
-	it('custom property set in SASS paser', () => {
-		sassDecls('a\n\t--custom-property-set:\n\t\tcolor: blue', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+	it('custom property set in SASS parser', () => {
+		expect(
+			isStandardSyntaxDeclaration(sassDecl('a\n\t--custom-property-set:\n\t\tcolor: blue')),
+		).toBe(true);
 	});
 
-	it('custom property set in SCSS paser', () => {
-		scssDecls('a { --custom-property-set: { color: blue; } }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+	it('custom property set in SCSS parser', () => {
+		expect(
+			isStandardSyntaxDeclaration(scssDecl('a { --custom-property-set: { color: blue; } }')),
+		).toBe(true);
 	});
 
-	it('custom property set in LESS paser', () => {
-		lessDecls('a { --custom-property-set: { color: blue; } }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+	it('custom property set in LESS parser', () => {
+		expect(
+			isStandardSyntaxDeclaration(lessDecl('a { --custom-property-set: { color: blue; } }')),
+		).toBe(true);
 	});
 
 	it('property with sass variable interpolation (only)', () => {
-		sassDecls('a\n\t#{$var}: 10px', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(sassDecl('a\n\t#{$var}: 10px'))).toBe(true);
 	});
 
 	it('property with scss variable interpolation (only)', () => {
-		scssDecls('a { #{$var}: 10px; }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('a { #{$var}: 10px; }'))).toBe(true);
 	});
 
 	it('property with sass variable interpolation (end)', () => {
-		sassDecls('a\n\tprop#{$var}: 10px', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(sassDecl('a\n\tprop#{$var}: 10px'))).toBe(true);
 	});
 
 	it('property with scss variable interpolation (end)', () => {
-		scssDecls('a { prop#{$var}: 10px; }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('a { prop#{$var}: 10px; }'))).toBe(true);
 	});
 
 	it('property with sass variable interpolation (middle)', () => {
-		sassDecls('a\n\tprop#{$var}erty: 10px', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(sassDecl('a\n\tprop#{$var}erty: 10px'))).toBe(true);
 	});
 
 	it('property with scss variable interpolation (middle)', () => {
-		scssDecls('a { prop#{$var}erty: 10px; }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('a { prop#{$var}erty: 10px; }'))).toBe(true);
 	});
 
 	it('property with less variable interpolation (only)', () => {
-		lessDecls('a { @{var}: 10px; }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(lessDecl('a { @{var}: 10px; }'))).toBe(true);
 	});
 
 	it('property with less variable interpolation (end)', () => {
-		lessDecls('a { prop@{var}: 10px; }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(lessDecl('a { prop@{var}: 10px; }'))).toBe(true);
 	});
 
 	it('property with less variable interpolation (middle)', () => {
-		lessDecls('a { prop@{var}erty: 10px; }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeTruthy();
-		});
+		expect(isStandardSyntaxDeclaration(lessDecl('a { prop@{var}erty: 10px; }'))).toBe(true);
 	});
 
 	it('sass var', () => {
-		sassDecls('$var: b', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(sassDecl('$var: b'))).toBe(false);
 	});
 
 	it('scss var', () => {
-		scssDecls('$var: b', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('$var: b'))).toBe(false);
 	});
 
 	it('scss var within namespace', () => {
-		scssDecls('namespace.$var: b', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('namespace.$var: b'))).toBe(false);
 	});
 
 	it('nested scss var within namespace', () => {
-		scssDecls('a { namespace.$var: b }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('a { namespace.$var: b }'))).toBe(false);
 	});
 
 	it('sass list', () => {
-		sassDecls('$list: (key: value, key2: value2)', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(sassDecl('$list: (key: value, key2: value2)'))).toBe(false);
 	});
 
 	it('scss list', () => {
-		scssDecls('$list: (key: value, key2: value2)', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('$list: (key: value, key2: value2)'))).toBe(false);
 	});
 
 	it('sass map', () => {
-		sassDecls('$map: (value, value2)', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(sassDecl('$map: (value, value2)'))).toBe(false);
 	});
 
 	it('scss map', () => {
-		scssDecls('$map: (value, value2)', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('$map: (value, value2)'))).toBe(false);
 	});
 
 	it('nested sass var', () => {
-		sassDecls('a\n\t$var: b', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(sassDecl('a\n\t$var: b'))).toBe(false);
 	});
 
 	it('nested scss var', () => {
-		scssDecls('a { $var: b }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('a { $var: b }'))).toBe(false);
 	});
 
 	it('nested sass list', () => {
-		sassDecls('a\n\t$list: (key: value, key2: value2)', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(sassDecl('a\n\t$list: (key: value, key2: value2)'))).toBe(
+			false,
+		);
 	});
 
 	it('nested scss list', () => {
-		scssDecls('a { $list: (key: value, key2: value2) }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('a { $list: (key: value, key2: value2) }'))).toBe(
+			false,
+		);
 	});
 
 	it('sass nested property', () => {
-		sassDecls('a\n\tborder:\n\t\tstyle: solid\n\t\tcolor: red', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(sassDecl('a\n\tborder:\n\t\tstyle: solid'))).toBe(false);
 	});
 
 	it('scss nested property', () => {
-		scssDecls('a { border: { style: solid; color: red; } }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('a { border: { style: solid; } }'))).toBe(false);
 	});
 
 	it('nested sass map', () => {
-		sassDecls('a\n\t$map: (value, value2)', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(sassDecl('a\n\t$map: (value, value2)'))).toBe(false);
 	});
 
 	it('nested scss map', () => {
-		scssDecls('a { $map: (value, value2) }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
-	});
-
-	it('less var', () => {
-		lessDecls('@var: b', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
-	});
-
-	it('nested less var', () => {
-		lessDecls('a { @var: b }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(scssDecl('a { $map: (value, value2) }'))).toBe(false);
 	});
 
 	it('less &:extend', () => {
-		lessDecls('a { &:extend(b) }', (decl) => {
-			expect(isStandardSyntaxDeclaration(decl)).toBeFalsy();
-		});
+		expect(isStandardSyntaxDeclaration(lessDecl('a { &:extend(b) }'))).toBe(false);
 	});
 });
 
-function decls(css, cb) {
-	postcss.parse(css).walkDecls(cb);
+function decl(css, parser = postcss) {
+	const list = [];
+
+	parser.parse(css).walkDecls((d) => list.push(d));
+
+	if (list.length === 1) {
+		return list[0];
+	}
+
+	throw new Error(`Expected length 1, but ${list.length}`);
 }
 
-function sassDecls(css, cb) {
-	sass.parse(css).walkDecls(cb);
+function sassDecl(css) {
+	return decl(css, postcssSass);
 }
 
-function scssDecls(css, cb) {
-	scss.parse(css).walkDecls(cb);
+function scssDecl(css) {
+	return decl(css, postcssScss);
 }
 
-function lessDecls(css, cb) {
-	less.parse(css).walkDecls(cb);
+function lessDecl(css) {
+	return decl(css, postcssLess);
 }