diff --git a/src/test/directives/style-map_test.ts b/src/test/directives/style-map_test.ts
index 830b935aa2..14c0bc9d22 100644
--- a/src/test/directives/style-map_test.ts
+++ b/src/test/directives/style-map_test.ts
@@ -19,7 +19,8 @@ import {html} from '../../lit-html.js';
 const ua = window.navigator.userAgent;
 const isChrome41 = ua.indexOf('Chrome/41') > 0;
 const isIE = ua.indexOf('Trident/') > 0;
-const testIfSupportsCSSVariables = isIE || isChrome41 ? test.skip : test;
+const testIfSupportsCSSVariables = (test: any) =>
+    isIE || isChrome41 ? test.skip : test;
 
 const assert = chai.assert;
 
@@ -78,7 +79,7 @@ suite('styleMap', () => {
     assert.equal(el.style.paddingBottom, '');
   });
 
-  testIfSupportsCSSVariables('adds and removes CSS variables', () => {
+  testIfSupportsCSSVariables(test)('adds and removes CSS variables', () => {
     renderStyleMap({'--size': '2px'});
     const el = container.firstElementChild as HTMLElement;
     assert.equal(el.style.getPropertyValue('--size'), '2px');
diff --git a/src/test/lib/render_test.ts b/src/test/lib/render_test.ts
index fb31d19516..4044661a92 100644
--- a/src/test/lib/render_test.ts
+++ b/src/test/lib/render_test.ts
@@ -22,20 +22,25 @@ const assert = chai.assert;
 const isTemplatePolyfilled =
     ((HTMLTemplateElement as any).decorate != null ||
      (window as any).ShadyDOM && (window as any).ShadyDOM.inUse);
-const testSkipForTemplatePolyfill = isTemplatePolyfilled ? test.skip : test;
+const testSkipForTemplatePolyfill = (test: any) =>
+    isTemplatePolyfilled ? test.skip : test;
 
 const isSafari10_0 =
-    (window.navigator.userAgent.indexOf('AppleWebKit/602') === -1);
-const testSkipSafari10_0 = isSafari10_0 ? test : test.skip;
+    (window.navigator.userAgent.indexOf('AppleWebKit/602') !== -1);
+const testSkipSafari10_0 = (test: any) => isSafari10_0 ? test.skip : test;
 
-const isChrome41 = (window.navigator.userAgent.indexOf('Chrome/41') === -1);
-const testSkipChrome41 = isChrome41 ? test : test.skip;
+const isChrome41 = (window.navigator.userAgent.indexOf('Chrome/41') !== -1);
+const testSkipChrome41 = (test: any) => isChrome41 ? test.skip : test;
 
-const testIfHasSymbol = (window as any).Symbol === undefined ? test.skip : test;
+const testIfHasSymbol = (test: any) =>
+    (window as any).Symbol === undefined ? test.skip : test;
 
 const ua = window.navigator.userAgent;
 const isIe = ua.indexOf('Trident/') > 0;
 
+const suiteIfCustomElementsAreSupported = (suite: any) =>
+    (window.customElements != null) ? suite : suite.skip;
+
 suite('render()', () => {
   let container: HTMLElement;
 
@@ -88,7 +93,7 @@ suite('render()', () => {
           children.filter((node) => node.nodeType !== Node.COMMENT_NODE));
     });
 
-    testIfHasSymbol('renders a Symbol', () => {
+    testIfHasSymbol(test)('renders a Symbol', () => {
       render(html`<div>${Symbol('A')}</div>`, container);
       assert.include(
           container.querySelector('div')!.textContent!.toLowerCase(), 'symbol');
@@ -375,14 +380,15 @@ suite('render()', () => {
           stripExpressionMarkers(container.innerHTML), '<div foo="bar"></div>');
     });
 
-    testIfHasSymbol('renders a Symbol to an attribute', () => {
+    testIfHasSymbol(test)('renders a Symbol to an attribute', () => {
       render(html`<div foo=${Symbol('A')}></div>`, container);
       assert.include(
           container.querySelector('div')!.getAttribute('foo')!.toLowerCase(),
           'symbol');
     });
 
-    testIfHasSymbol('renders a Symbol in an array to an attribute', () => {
+    testIfHasSymbol(
+        test)('renders a Symbol in an array to an attribute', () => {
       render(html`<div foo=${[Symbol('A')]}></div>`, container);
       assert.include(
           container.querySelector('div')!.getAttribute('foo')!.toLowerCase(),
@@ -793,7 +799,7 @@ suite('render()', () => {
       assert.strictEqual((container.firstElementChild as any).foo, 1234);
     });
 
-    testSkipChrome41(
+    testSkipChrome41(test)(
         'event listeners can see events fired by dynamic children', () => {
           // This tests that node directives are called in the commit phase, not
           // the setValue phase
@@ -840,43 +846,43 @@ suite('render()', () => {
 
   suite('<table>', () => {
     testSkipForTemplatePolyfill(
-        'renders nested templates within table content', () => {
-          let table = html`<table>${html`<tr>${html`<td></td>`}</tr>`}</table>`;
-          render(table, container);
-          assert.equal(
-              stripExpressionMarkers(container.innerHTML),
-              '<table><tr><td></td></tr></table>');
+        test)('renders nested templates within table content', () => {
+      let table = html`<table>${html`<tr>${html`<td></td>`}</tr>`}</table>`;
+      render(table, container);
+      assert.equal(
+          stripExpressionMarkers(container.innerHTML),
+          '<table><tr><td></td></tr></table>');
 
-          table = html`<tbody>${html`<tr></tr>`}</tbody>`;
-          render(table, container);
-          assert.equal(
-              stripExpressionMarkers(container.innerHTML),
-              '<tbody><tr></tr></tbody>');
+      table = html`<tbody>${html`<tr></tr>`}</tbody>`;
+      render(table, container);
+      assert.equal(
+          stripExpressionMarkers(container.innerHTML),
+          '<tbody><tr></tr></tbody>');
 
-          table = html`<table><tr></tr>${html`<tr></tr>`}</table>`;
-          render(table, container);
-          assert.equal(
-              stripExpressionMarkers(container.innerHTML),
-              '<table><tbody><tr></tr><tr></tr></tbody></table>');
+      table = html`<table><tr></tr>${html`<tr></tr>`}</table>`;
+      render(table, container);
+      assert.equal(
+          stripExpressionMarkers(container.innerHTML),
+          '<table><tbody><tr></tr><tr></tr></tbody></table>');
 
-          table = html`<table><tr><td></td>${html`<td></td>`}</tr></table>`;
-          render(table, container);
-          assert.equal(
-              stripExpressionMarkers(container.innerHTML),
-              '<table><tbody><tr><td></td><td></td></tr></tbody></table>');
+      table = html`<table><tr><td></td>${html`<td></td>`}</tr></table>`;
+      render(table, container);
+      assert.equal(
+          stripExpressionMarkers(container.innerHTML),
+          '<table><tbody><tr><td></td><td></td></tr></tbody></table>');
 
-          table = html`<table><tr><td></td>${html`<td></td>`}${
-              html`<td></td>`}</tr></table>`;
-          render(table, container);
-          assert.equal(
-              stripExpressionMarkers(container.innerHTML),
-              '<table><tbody><tr><td></td><td></td><td></td></tr></tbody></table>');
-        });
+      table = html`<table><tr><td></td>${html`<td></td>`}${
+          html`<td></td>`}</tr></table>`;
+      render(table, container);
+      assert.equal(
+          stripExpressionMarkers(container.innerHTML),
+          '<table><tbody><tr><td></td><td></td><td></td></tr></tbody></table>');
+    });
 
     // On Safari 10.0 (but not 10.1), the attribute value "<table>" is
     // escaped to "&lt;table&gt;". That shouldn't cause this test to
     // fail, so we skip
-    testSkipSafari10_0(
+    testSkipSafari10_0(test)(
         'renders quoted attributes with "<table>" before an expression', () => {
           const template = html`<div a="<table>${'foo'}"></div>`;
           render(template, container);
@@ -1013,10 +1019,7 @@ suite('render()', () => {
     });
   });
 
-  const suiteIfCustomElementsAreSupported =
-      (window.customElements != null) ? suite : suite.skip;
-
-  suiteIfCustomElementsAreSupported('custom elements', () => {
+  suiteIfCustomElementsAreSupported(suite)('custom elements', () => {
     class PropertySetterElement extends HTMLElement {
       public readonly calledSetter = false;
       private _value?: string = undefined;
diff --git a/src/test/lib/shady-render-apply_test.ts b/src/test/lib/shady-render-apply_test.ts
index 366c5d0e74..8f66ca7bee 100644
--- a/src/test/lib/shady-render-apply_test.ts
+++ b/src/test/lib/shady-render-apply_test.ts
@@ -19,6 +19,9 @@ import {renderShadowRoot} from '../test-utils/shadow-root.js';
 
 const assert = chai.assert;
 
+const testIfUsingNativeCSSVariables = (test: any) =>
+    (window.ShadyCSS && !window.ShadyCSS.nativeCss ? test.skip : test);
+
 suite('shady-render @apply', () => {
   test('styles with css custom properties using @apply render', function() {
     const container = document.createElement('scope-5');
@@ -127,9 +130,7 @@ suite('shady-render @apply', () => {
 
   // TODO(sorvell): remove skip when this ShadyCSS PR is merged:
   // https://github.com/webcomponents/shadycss/pull/227.
-  const testOrSkip =
-      (window.ShadyCSS && !window.ShadyCSS.nativeCss ? test.skip : test);
-  testOrSkip(
+  testIfUsingNativeCSSVariables(test)(
       '@apply styles flow to custom elements that render in connectedCallback',
       () => {
         class E extends HTMLElement {