diff --git a/src/format.js b/src/format.js
new file mode 100644
index 00000000..36ec7b8f
--- /dev/null
+++ b/src/format.js
@@ -0,0 +1,91 @@
+const chalk = require('chalk');
+const { minify } = require('html-minifier');
+const { makeReplacements } = require('./replacements');
+
+const belowThreshold = (id, expected, categories) => {
+  const category = categories.find((c) => c.id === id);
+  if (!category) {
+    console.warn(`Could not find category ${chalk.yellow(id)}`);
+  }
+  const actual = category ? category.score : Number.MAX_SAFE_INTEGER;
+  return actual < expected;
+};
+
+const getError = (id, expected, categories, audits) => {
+  const category = categories.find((c) => c.id === id);
+
+  const categoryError = `Expected category ${chalk.cyan(
+    category.title,
+  )} to be greater or equal to ${chalk.green(expected)} but got ${chalk.red(
+    category.score !== null ? category.score : 'unknown',
+  )}`;
+
+  const categoryAudits = category.auditRefs
+    .filter(({ weight, id }) => weight > 0 && audits[id].score < 1)
+    .map((ref) => {
+      const audit = audits[ref.id];
+      return `   '${chalk.cyan(
+        audit.title,
+      )}' received a score of ${chalk.yellow(audit.score)}`;
+    })
+    .join('\n');
+
+  return { message: categoryError, details: categoryAudits };
+};
+
+const formatShortSummary = (categories) => {
+  return categories
+    .map(({ title, score }) => `${title}: ${Math.round(score * 100)}`)
+    .join(', ');
+};
+
+const formatResults = ({ results, thresholds }) => {
+  const runtimeError = results.lhr.runtimeError;
+
+  const categories = Object.values(results.lhr.categories).map(
+    ({ title, score, id, auditRefs }) => ({ title, score, id, auditRefs }),
+  );
+
+  const categoriesBelowThreshold = Object.entries(thresholds).filter(
+    ([id, expected]) => belowThreshold(id, expected, categories),
+  );
+
+  const errors = categoriesBelowThreshold.map(([id, expected]) =>
+    getError(id, expected, categories, results.lhr.audits),
+  );
+
+  const summary = categories.map(({ title, score, id }) => ({
+    title,
+    score,
+    id,
+    ...(thresholds[id] ? { threshold: thresholds[id] } : {}),
+  }));
+
+  const shortSummary = formatShortSummary(categories);
+
+  const formattedReport = makeReplacements(results.report);
+
+  // Pull some additional details to pass to App
+  const { formFactor, locale } = results.lhr.configSettings;
+  const installable = results.lhr.audits['installable-manifest']?.score === 1;
+  const details = { installable, formFactor, locale };
+
+  const report = minify(formattedReport, {
+    removeAttributeQuotes: true,
+    collapseWhitespace: true,
+    removeRedundantAttributes: true,
+    removeOptionalTags: true,
+    removeEmptyElements: true,
+    minifyCSS: true,
+    minifyJS: true,
+  });
+
+  return { summary, shortSummary, details, report, errors, runtimeError };
+};
+
+module.exports = {
+  belowThreshold,
+  getError,
+  formatShortSummary,
+  formatResults,
+};
diff --git a/src/format.test.js b/src/format.test.js
new file mode 100644
index 00000000..59afb1fe
--- /dev/null
+++ b/src/format.test.js
@@ -0,0 +1,219 @@
+const {
+  belowThreshold,
+  getError,
+  formatShortSummary,
+  formatResults,
+} = require('./format');
+
+// Strip ANSI color codes from strings, as they make CI sad.
+const stripAnsiCodes = (str) =>
+  str.replace(
+    // eslint-disable-next-line no-control-regex
+    /[\u001b\u009b][[()#;?]*(?:[0-9]{1,4}(?:;[0-9]{0,4})*)?[0-9A-ORZcf-nqry=><]/g,
+    '',
+  );
+
+describe('format', () => {
+  const getCategories = ({ score }) => [
+    {
+      title: 'Performance',
+      score,
+      id: 'performance',
+      auditRefs: [
+        { weight: 1, id: 'is-crawlable' },
+        { weight: 1, id: 'robots-txt' },
+        { weight: 1, id: 'tap-targets' },
+      ],
+    },
+  ];
+  const audits = {
+    'is-crawlable': {
+      id: 'is-crawlable',
+      title: 'Page isn’t blocked from indexing',
+      description:
+        "Search engines are unable to include your pages in search results if they don't have permission to crawl them. [Learn more](https://web.dev/is-crawable/).",
+      score: 1,
+    },
+    'robots-txt': {
+      id: 'robots-txt',
+      title: 'robots.txt is valid',
+      description:
+        'If your robots.txt file is malformed, crawlers may not be able to understand how you want your website to be crawled or indexed. [Learn more](https://web.dev/robots-txt/).',
+      score: 0,
+    },
+    'tap-targets': {
+      id: 'tap-targets',
+      title: 'Tap targets are sized appropriately',
+      description:
+        'Interactive elements like buttons and links should be large enough (48x48px), and have enough space around them, to be easy enough to tap without overlapping onto other elements. [Learn more](https://web.dev/tap-targets/).',
+      score: 0.5,
+    },
+  };
+
+  const formattedError = {
+    details:
+      "   'robots.txt is valid' received a score of 0\n" +
+      "   'Tap targets are sized appropriately' received a score of 0.5",
+    message:
+      'Expected category Performance to be greater or equal to 1 but got 0.5',
+  };
+
+  describe('belowThreshold', () => {
+    const categories = [
+      { title: 'Performance', score: 0.9, id: 'performance' },
+      { title: 'Accessibility', score: 0.8, id: 'accessibility' },
+    ];
+
+    it('returns false when the score is above the threshold', () => {
+      expect(belowThreshold('performance', 0.8, categories)).toBe(false);
+    });
+
+    it('returns false when the category is not found', () => {
+      console.warn = jest.fn();
+      const result = belowThreshold('seo', 0.8, categories);
+      expect(console.warn).toHaveBeenCalled();
+      expect(result).toBe(false);
+    });
+
+    it('returns true when the score is below the threshold', () => {
+      expect(belowThreshold('performance', 1, categories)).toBe(true);
+    });
+  });
+
+  describe('getError', () => {
+    it('returns an expected error message and list of details with valid score', () => {
+      const errorMessage = getError(
+        'performance',
+        1,
+        getCategories({ score: 0.5 }),
+        audits,
+      );
+      expect(stripAnsiCodes(errorMessage.details)).toEqual(
+        formattedError.details,
+      );
+      expect(stripAnsiCodes(errorMessage.message)).toEqual(
+        formattedError.message,
+      );
+    });
+
+    it('returns an expected error message and list of details without valid score', () => {
+      const errorMessage = getError(
+        'performance',
+        1,
+        getCategories({ score: null }),
+        audits,
+      );
+      expect(stripAnsiCodes(errorMessage.message)).toContain(
+        'to be greater or equal to 1 but got unknown',
+      );
+    });
+  });
+
+  describe('formatShortSummary', () => {
+    const categories = [
+      { title: 'Performance', score: 1, id: 'performance' },
+      { title: 'Accessibility', score: 0.9, id: 'accessibility' },
+      { title: 'Best Practices', score: 0.8, id: 'best-practices' },
+      { title: 'SEO', score: 0.7, id: 'seo' },
+      { title: 'PWA', score: 0.6, id: 'pwa' },
+    ];
+
+    it('should return a shortSummary containing scores if available', () => {
+      const shortSummary = formatShortSummary(categories);
+      expect(shortSummary).toEqual(
+        'Performance: 100, Accessibility: 90, Best Practices: 80, SEO: 70, PWA: 60',
+      );
+    });
+  });
+
+  describe('formatResults', () => {
+    const getResults = () => ({
+      lhr: {
+        lighthouseVersion: '9.6.3',
+        requestedUrl: 'http://localhost:5100/404.html',
+        finalUrl: 'http://localhost:5100/404.html',
+        audits,
+        configSettings: {},
+        categories: getCategories({ score: 0.5 }),
+      },
+      artifacts: {},
+      report: '<!doctype html>\n' + '<html lang="en">Hi</html>\n',
+    });
+
+    it('should return formatted results', () => {
+      expect(formatResults({ results: getResults(), thresholds: {} })).toEqual({
+        details: {
+          formFactor: undefined,
+          installable: false,
+          locale: undefined,
+        },
+        errors: [],
+        report: '<!doctype html><html lang=en>Hi',
+        shortSummary: 'Performance: 50',
+        summary: [{ id: 'performance', score: 0.5, title: 'Performance' }],
+      });
+    });
+
+    it('should return formatted results with passing thresholds', () => {
+      const thresholds = {
+        performance: 0.1,
+      };
+      const formattedResults = formatResults({
+        results: getResults(),
+        thresholds,
+      });
+      expect(formattedResults.errors).toEqual([]);
+      expect(formattedResults.summary).toEqual([
+        {
+          id: 'performance',
+          score: 0.5,
+          title: 'Performance',
+          threshold: 0.1,
+        },
+      ]);
+    });
+
+    it('should return formatted results with failing thresholds', () => {
+      const thresholds = {
+        performance: 1,
+      };
+      const formattedResults = formatResults({
+        results: getResults(),
+        thresholds,
+      });
+      expect(stripAnsiCodes(formattedResults.errors[0].message)).toEqual(
+        formattedError.message,
+      );
+      expect(stripAnsiCodes(formattedResults.errors[0].details)).toEqual(
+        formattedError.details,
+      );
+      expect(formattedResults.summary).toEqual([
+        {
+          id: 'performance',
+          score: 0.5,
+          title: 'Performance',
+          threshold: 1,
+        },
+      ]);
+    });
+
+    it('should use supplied config settings and data to populate `details`', () => {
+      const results = getResults();
+      results.lhr.configSettings = {
+        locale: 'es',
+        formFactor: 'desktop',
+      };
+      results.lhr.audits['installable-manifest'] = {
+        id: 'installable-manifest',
+        score: 1,
+      };
+
+      const formattedResults = formatResults({ results, thresholds: {} });
+      expect(formattedResults.details).toEqual({
+        formFactor: 'desktop',
+        installable: true,
+        locale: 'es',
+      });
+    });
+  });
+});
diff --git a/src/index.js b/src/index.js
index dcf14451..2d6b7989 100644
--- a/src/index.js
+++ b/src/index.js
@@ -4,11 +4,10 @@ const express = require('express');
 const compression = require('compression');
 const chalk = require('chalk');
 const fs = require('fs').promises;
-const minify = require('html-minifier').minify;
 const { getConfiguration } = require('./config');
 const { getSettings } = require('./settings');
 const { getBrowserPath, runLighthouse } = require('./lighthouse');
-const { makeReplacements } = require('./replacements');
+const { formatResults } = require('./format');
 
 const getServer = ({ serveDir, auditUrl }) => {
   if (auditUrl) {
@@ -47,87 +46,18 @@ const getServer = ({ serveDir, auditUrl }) => {
   return { server };
 };
 
-const belowThreshold = (id, expected, categories) => {
-  const category = categories.find((c) => c.id === id);
-  if (!category) {
-    console.warn(`Could not find category ${chalk.yellow(id)}`);
-  }
-  const actual = category ? category.score : Number.MAX_SAFE_INTEGER;
-  return actual < expected;
-};
-
-const getError = (id, expected, categories, audits) => {
-  const category = categories.find((c) => c.id === id);
-
-  const categoryError = `Expected category ${chalk.cyan(
-    category.title,
-  )} to be greater or equal to ${chalk.green(expected)} but got ${chalk.red(
-    category.score !== null ? category.score : 'unknown',
-  )}`;
-
-  const categoryAudits = category.auditRefs
-    .filter(({ weight, id }) => weight > 0 && audits[id].score < 1)
-    .map((ref) => {
-      const audit = audits[ref.id];
-      return `   '${chalk.cyan(
-        audit.title,
-      )}' received a score of ${chalk.yellow(audit.score)}`;
-    })
-    .join('\n');
-
-  return { message: categoryError, details: categoryAudits };
-};
-
-const formatResults = ({ results, thresholds }) => {
-  const categories = Object.values(results.lhr.categories).map(
-    ({ title, score, id, auditRefs }) => ({ title, score, id, auditRefs }),
-  );
-
-  const categoriesBelowThreshold = Object.entries(thresholds).filter(
-    ([id, expected]) => belowThreshold(id, expected, categories),
-  );
-
-  const errors = categoriesBelowThreshold.map(([id, expected]) =>
-    getError(id, expected, categories, results.lhr.audits),
-  );
-
-  const summary = categories.map(({ title, score, id }) => ({
-    title,
-    score,
-    id,
-    ...(thresholds[id] ? { threshold: thresholds[id] } : {}),
-  }));
-
-  const shortSummary = categories
-    .map(({ title, score }) => `${title}: ${Math.round(score * 100)}`)
-    .join(', ');
-
-  const formattedReport = makeReplacements(results.report);
-
-  // Pull some additional details to pass to App
-  const { formFactor, locale } = results.lhr.configSettings;
-  const installable = results.lhr.audits['installable-manifest'].score === 1;
-  const details = { installable, formFactor, locale };
-
-  const report = minify(formattedReport, {
-    removeAttributeQuotes: true,
-    collapseWhitespace: true,
-    removeRedundantAttributes: true,
-    removeOptionalTags: true,
-    removeEmptyElements: true,
-    minifyCSS: true,
-    minifyJS: true,
-  });
-
-  return { summary, shortSummary, details, report, errors };
-};
-
 const persistResults = async ({ report, path }) => {
   await fs.mkdir(dirname(path), { recursive: true });
   await fs.writeFile(path, report);
 };
 
 const getUtils = ({ utils }) => {
+  // This function checks to see if we're running within the Netlify Build system,
+  // and if so, we use the util functions. If not, we're likely running locally
+  // so fall back using console.log to emulate the output.
+
+  // If available, fails the Netlify build with the supplied message
+  // https://docs.netlify.com/integrations/build-plugins/create-plugins/#error-reporting
   const failBuild =
     (utils && utils.build && utils.build.failBuild) ||
     ((message, { error } = {}) => {
@@ -135,6 +65,8 @@ const getUtils = ({ utils }) => {
       process.exitCode = 1;
     });
 
+  // If available, displays the summary in the Netlify UI Deploy Summary section
+  // https://docs.netlify.com/integrations/build-plugins/create-plugins/#logging
   const show =
     (utils && utils.status && utils.status.show) ||
     (({ summary }) => console.log(summary));
@@ -170,10 +102,11 @@ const runAudit = async ({
     if (error) {
       return { error };
     } else {
-      const { summary, shortSummary, details, report, errors } = formatResults({
-        results,
-        thresholds,
-      });
+      const { summary, shortSummary, details, report, errors, runtimeError } =
+        formatResults({
+          results,
+          thresholds,
+        });
 
       if (output_path) {
         await persistResults({ report, path: join(serveDir, output_path) });
@@ -185,6 +118,7 @@ const runAudit = async ({
         details,
         report,
         errors,
+        runtimeError,
       };
     }
   } catch (error) {
@@ -237,28 +171,45 @@ const processResults = ({ data, errors }) => {
   return {
     error: err,
     summary: data
-      .map(({ path, url, summary, shortSummary, details, report }) => {
-        const obj = { report, details };
-
-        if (summary) {
-          obj.summary = summary.reduce((acc, item) => {
-            acc[item.id] = Math.round(item.score * 100);
-            return acc;
-          }, {});
-        }
-
-        if (path) {
-          obj.path = path;
-          reports.push(obj);
-          return `Summary for path '${chalk.magenta(path)}': ${shortSummary}`;
-        }
-        if (url) {
-          obj.url = url;
-          reports.push(obj);
-          return `Summary for url '${chalk.magenta(url)}': ${shortSummary}`;
-        }
-        return `${shortSummary}`;
-      })
+      .map(
+        ({
+          path,
+          url,
+          summary,
+          shortSummary,
+          details,
+          report,
+          runtimeError,
+        }) => {
+          const obj = { report, details };
+
+          if (!runtimeError && summary) {
+            obj.summary = summary.reduce((acc, item) => {
+              acc[item.id] = Math.round(item.score * 100);
+              return acc;
+            }, {});
+          }
+
+          if (runtimeError) {
+            reports.push(obj);
+            return `Error testing '${chalk.magenta(path || url)}': ${
+              runtimeError.message
+            }`;
+          }
+
+          if (path) {
+            obj.path = path;
+            reports.push(obj);
+            return `Summary for path '${chalk.magenta(path)}': ${shortSummary}`;
+          }
+          if (url) {
+            obj.url = url;
+            reports.push(obj);
+            return `Summary for url '${chalk.magenta(url)}': ${shortSummary}`;
+          }
+          return `${shortSummary}`;
+        },
+      )
       .join('\n'),
     extraData: reports,
   };
@@ -280,7 +231,7 @@ module.exports = {
       const allErrors = [];
       const data = [];
       for (const { serveDir, path, url, thresholds, output_path } of audits) {
-        const { errors, summary, shortSummary, details, report } =
+        const { errors, summary, shortSummary, details, report, runtimeError } =
           await runAudit({
             serveDir,
             path,
@@ -289,9 +240,13 @@ module.exports = {
             output_path,
             settings,
           });
-        if (summary) {
+
+        if (summary && !runtimeError) {
           console.log({ results: summary });
         }
+        if (runtimeError) {
+          console.log({ runtimeError });
+        }
 
         const fullPath = [serveDir, path].join('/');
         if (report) {
@@ -299,7 +254,9 @@ module.exports = {
           console.log(
             `Report collected: audited_uri: '${chalk.magenta(
               url || fullPath,
-            )}', html_report_size: ${chalk.magenta(size / 1024)} KiB`,
+            )}', html_report_size: ${chalk.magenta(
+              +(size / 1024).toFixed(2),
+            )} KiB`,
           );
         }
 
@@ -313,6 +270,7 @@ module.exports = {
           shortSummary,
           details,
           report,
+          runtimeError,
         });
       }
 
diff --git a/src/lighthouse.js b/src/lighthouse.js
index 56bb14ef..e009fd81 100644
--- a/src/lighthouse.js
+++ b/src/lighthouse.js
@@ -54,9 +54,6 @@ const runLighthouse = async (browserPath, url, settings) => {
       },
       settings,
     );
-    if (results.lhr.runtimeError) {
-      throw new Error(results.lhr.runtimeError.message);
-    }
     return results;
   } finally {
     if (chrome) {