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Cypress mochawesome report only shows the last spec

You ran cypress run across twelve spec files. The mochawesome report opens fine — and contains exactly one of them. Run it again and it is a different one.

Nothing is lost by the tests. The reports are overwriting each other.

Why it happens

Cypress does not run your suite as one Mocha run. It runs each spec file as its own run, in a fresh browser context, and starts the reporter from scratch every time.

mochawesome writes mochawesome.json and mochawesome.html with overwrite: true by default. Spec 1 writes the file, spec 2 replaces it, and the last spec to finish is the report you see. In a parallel or randomised order, "last" changes from run to run.

Fix 1: one JSON per spec, merge, render

Tell mochawesome to keep every spec's output, as JSON only:

// cypress.config.js
module.exports = defineConfig({
  reporter: "mochawesome",
  reporterOptions: {
    reportDir: "cypress/results",
    overwrite: false,
    html: false,
    json: true,
  },
});

With overwrite: false the files come out as mochawesome.json, mochawesome_001.json, mochawesome_002.json and so on. Then merge them and render once:

rm -rf cypress/results
npx cypress run || true
npx mochawesome-merge "cypress/results/*.json" -o merged.json
npx marge merged.json --reportDir mochawesome-report --inline

marge is the CLI of mochawesome-report-generator. --inline puts the CSS and JS into the HTML instead of an assets/ folder beside it, which matters as soon as the file leaves the runner.

Write merged.json outside the results folder. Put it inside and the next run's glob merges the previous merged file back in, doubling every test.

Fix 2: cypress-mochawesome-reporter

If you would rather not script the merge, cypress-mochawesome-reporter does it inside Cypress:

// cypress.config.js
module.exports = defineConfig({
  reporter: "cypress-mochawesome-reporter",
  reporterOptions: { embeddedScreenshots: true, inlineAssets: true },
  e2e: {
    setupNodeEvents(on) {
      require("cypress-mochawesome-reporter/plugin")(on);
    },
  },
});

// cypress/support/e2e.js
import "cypress-mochawesome-reporter/register";

It merges the per-spec results when cypress run finishes and, with embeddedScreenshots, puts the failure screenshot next to the failing test — which the plain mochawesome setup does not do on its own. Miss either the plugin line or the support import and you are back to one spec, or to no report at all.

The other ways the merge goes wrong

Symptom Cause Fix
Tests from yesterday in today's report Old JSON files still in the results folder rm -rf cypress/results before cypress run
Every test appears twice merged.json written inside the globbed dir Write the merged file elsewhere
No report when a test fails in CI cypress run exits 1, later steps skipped if: always() / when: always on merge + render
Report has no styling once downloaded assets/ folder left behind marge --inline, or upload the whole folder
No files found from mochawesome-merge Unquoted glob expanded by the shell, or html: true only Quote the glob; set json: true
Parallel CI shards each have a fragment Each machine merged only its own specs Collect every shard's JSON, merge once at the end

In CI

- name: Cypress
  run: npx cypress run

- name: Build mochawesome report
  if: always()
  run: |
    npx mochawesome-merge "cypress/results/*.json" -o merged.json
    npx marge merged.json --reportDir mochawesome-report --inline

Then get it read

A merged report sitting in a zipped build artifact is still one download and an unzip away from anyone looking at it, and it expires under retention.

Publish mochawesome-report/ instead and the report is a link that opens in the browser. Publish to the same report on every run and each build becomes a revision, so the run where a flaky test failed is still there next week. Reviewers comment on the failing test itself instead of screenshotting it into chat (comment on HTML). Scripts run in a sandboxed iframe, so the mochawesome filters and charts keep working.

Limits: entry HTML 5 MB; assets 25 MB per file, 250 MB and 500 files per report. A report with embedded base64 screenshots grows fast — keep an eye on the 5 MB entry limit, or let screenshots upload as separate files.

Try it

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