fix: support Cypress versions before 10 (#9)

README.md

@@ -35,6 +35,20 @@ module.exports = defineConfig({
 
 **Important:** return the `config` object from the `setupNodeEvents` function.
 
+### Cypress versions before v10
+
+```js
+// cypress/plugins/index.js
+// https://github.com/bahmutov/cypress-split
+const cypressSplit = require('cypress-split')
+
+module.exports = (on, config) => {
+  cypressSplit(on, config)
+  // IMPORTANT: return the config object
+  return config
+})
+```
+
 Now update your CI script:
 
 ### GitLab CI

src/index.js

@@ -125,7 +125,15 @@ function cypressSplit(on, config) {
     if (splitSpecs.length) {
       debug('setting the spec pattern to')
       debug(splitSpecs)
-      config.specPattern = splitSpecs
+      if (config.integrationFolder) {
+        debug('setting test files')
+        config.testFiles = splitSpecs.map((name) =>
+          path.relative(config.integrationFolder, name),
+        )
+      } else {
+        // Cypress v10+
+        config.specPattern = splitSpecs
+      }
     } else {
       // copy the empty spec file from our source folder into temp folder
       const tempFilename = path.join(