diff --git a/.circleci/config.yml b/.circleci/config.yml
index 635b798f621c3e..21f1be785db934 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -71,29 +71,62 @@ jobs:
       - run:
           name: material-ui-icons
           command: |
-            if [[ ((`git diff --raw master | grep packages/material-ui-icons` > 0))]]; then
+            # latest commit
+            LATEST_COMMIT=$(git rev-parse HEAD)
+
+            # latest commit where packages/material-ui-icons was changed
+            FOLDER_COMMIT=$(git log -1 --format=format:%H --full-diff packages/material-ui-icons)
+
+            if [ $FOLDER_COMMIT = $LATEST_COMMIT ]; then
               echo "changes, let's run the tests"
               cd packages/material-ui-icons && yarn test
             else
-              echo "no changes "
+              echo "no changes"
             fi
       - run:
           name: material-ui-codemod
           command: |
-            if [[ ((`git diff --raw master | grep packages/material-ui-codemod` > 0))]]; then
+            # latest commit
+            LATEST_COMMIT=$(git rev-parse HEAD)
+
+            # latest commit where packages/material-ui-codemod was changed
+            FOLDER_COMMIT=$(git log -1 --format=format:%H --full-diff packages/material-ui-codemod)
+
+            if [ $FOLDER_COMMIT = $LATEST_COMMIT ]; then
               echo "changes, let's run the tests"
               cd packages/material-ui-codemod && yarn test
             else
-              echo "no changes "
+              echo "no changes"
+            fi
+      - run:
+          name: material-ui-lab
+          command: |
+            # latest commit
+            LATEST_COMMIT=$(git rev-parse HEAD)
+
+            # latest commit where packages/material-ui-lab was changed
+            FOLDER_COMMIT=$(git log -1 --format=format:%H --full-diff packages/material-ui-lab)
+
+            if [ $FOLDER_COMMIT = $LATEST_COMMIT ]; then
+              echo "changes, let's run the tests"
+              cd packages/material-ui-lab && yarn test
+            else
+              echo "no changes"
             fi
       - run:
           name: eslint-plugin-material-ui
           command: |
-            if [[ ((`git diff --raw master | grep packages/eslint-plugin-material-ui` > 0))]]; then
+            # latest commit
+            LATEST_COMMIT=$(git rev-parse HEAD)
+
+            # latest commit where packages/eslint-plugin-material-ui was changed
+            FOLDER_COMMIT=$(git log -1 --format=format:%H --full-diff packages/eslint-plugin-material-ui)
+
+            if [ $FOLDER_COMMIT = $LATEST_COMMIT ]; then
               echo "changes, let's run the tests"
               cd packages/eslint-plugin-material-ui && yarn test
             else
-              echo "no changes "
+              echo "no changes"
             fi
   test_build:
     <<: *defaults
diff --git a/packages/material-ui-icons/builder.js b/packages/material-ui-icons/builder.js
index a9a372ee94799b..17f3433bb76779 100755
--- a/packages/material-ui-icons/builder.js
+++ b/packages/material-ui-icons/builder.js
@@ -133,7 +133,8 @@ async function worker({ svgPath, options, renameFilter, template }) {
     .replace(/ clip-path=".+?"/g, '') // Fix visibility issue and save some bytes.
     .replace(/<clipPath.+?<\/clipPath>/g, ''); // Remove unused definitions
 
-  const size = Number(svgPath.match(/^.*_([0-9]+)px.svg$/)[1]);
+  const sizeMatch = svgPath.match(/^.*_([0-9]+)px.svg$/);
+  const size = sizeMatch ? Number(sizeMatch[1]) : null;
 
   if (size !== 24) {
     const scale = Math.round((24 / size) * 100) / 100; // Keep a maximum of 2 decimals
diff --git a/packages/material-ui-icons/builder.test.js b/packages/material-ui-icons/builder.test.js
index 4b0c454d536a42..c0069f753ee18d 100644
--- a/packages/material-ui-icons/builder.test.js
+++ b/packages/material-ui-icons/builder.test.js
@@ -100,7 +100,7 @@ describe('builder', () => {
         'svg',
         '000000',
         'transparent',
-        'dice-six-faces-four.js',
+        'Dice-six-faces-four.js',
       );
       assert.strictEqual(fs.existsSync(actualFilePath), true);