diff --git a/.gitignore b/.gitignore
index d780a15..f6f6d07 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,8 +1,6 @@
-node_modules
-lib
-test/service-account-key.json
-test/functions/integrify.js
 .nyc_output
-coverage
 .vscode
-firestore-debug.log
+*-debug.log
+coverage
+lib
+node_modules
diff --git a/src/rules/replicateAttributes.ts b/src/rules/replicateAttributes.ts
index e41f259..4fb7e99 100644
--- a/src/rules/replicateAttributes.ts
+++ b/src/rules/replicateAttributes.ts
@@ -68,6 +68,7 @@ export function integrifyReplicateAttributes(
 
       // Call "pre" hook if defined
       const promises = [];
+      // istanbul ignore else
       if (rule.hooks && rule.hooks.pre) {
         promises.push(rule.hooks.pre(change, context));
         console.log(`integrify: Running pre-hook: ${rule.hooks.pre}`);
diff --git a/test/functions/index.js b/test/functions/index.js
index 8718136..033a6b8 100644
--- a/test/functions/index.js
+++ b/test/functions/index.js
@@ -1,5 +1,4 @@
 const { integrify } = require('../../lib');
-const { setState } = require('./stateMachine');
 
 const functions = require('firebase-functions');
 const admin = require('firebase-admin');
@@ -34,8 +33,10 @@ module.exports.replicateMasterToDetail = integrify({
     },
   ],
   hooks: {
-    pre: (change, context) => {
-      setState({ change, context });
+    pre: async (change, context) => {
+      await db.collection('prehooks').add({
+        message: '[788a32e05504] REPLICATE_ATTRIBUTES prehook was called!',
+      });
     },
   },
 });
@@ -57,8 +58,10 @@ module.exports.deleteReferencesToMaster = integrify({
     },
   ],
   hooks: {
-    pre: (snap, context) => {
-      setState({ snap, context });
+    pre: async (snap, context) => {
+      await db.collection('prehooks').add({
+        message: '[6a8f4f8f090c] DELETE_REFERENCES prehook was called!',
+      });
     },
   },
 });
diff --git a/test/functions/integrify.rules.js b/test/functions/integrify.rules.js
index 3d500ed..64b3bcd 100644
--- a/test/functions/integrify.rules.js
+++ b/test/functions/integrify.rules.js
@@ -3,11 +3,11 @@ module.exports = [
     rule: 'REPLICATE_ATTRIBUTES',
     name: 'replicateMasterToDetailFromFile',
     source: {
-      collection: 'master',
+      collection: 'rules-file-master',
     },
     targets: [
       {
-        collection: 'detail1',
+        collection: 'rules-file-detail1',
         foreignKey: 'masterId',
         attributeMapping: {
           masterField1: 'detail1Field1',
@@ -15,7 +15,7 @@ module.exports = [
         },
       },
       {
-        collection: 'detail2',
+        collection: 'rules-file-detail2',
         foreignKey: 'masterId',
         attributeMapping: {
           masterField1: 'detail2Field1',
@@ -29,15 +29,15 @@ module.exports = [
     rule: 'DELETE_REFERENCES',
     name: 'deleteReferencesToMasterFromFile',
     source: {
-      collection: 'master',
+      collection: 'rules-file-master',
     },
     targets: [
       {
-        collection: 'detail1',
+        collection: 'rules-file-detail1',
         foreignKey: 'masterId',
       },
       {
-        collection: 'detail2',
+        collection: 'rules-file-detail2',
         foreignKey: 'masterId',
         isCollectionGroup: true,
       },
@@ -47,11 +47,11 @@ module.exports = [
     rule: 'MAINTAIN_COUNT',
     name: 'maintainFavoritesCountFromFile',
     source: {
-      collection: 'favorites',
+      collection: 'rules-file-favorites',
       foreignKey: 'articleId',
     },
     target: {
-      collection: 'articles',
+      collection: 'rules-file-articles',
       attribute: 'favoritesCount',
     },
   },
diff --git a/test/functions/stateMachine.js b/test/functions/stateMachine.js
deleted file mode 100644
index 77bea28..0000000
--- a/test/functions/stateMachine.js
+++ /dev/null
@@ -1,4 +0,0 @@
-const state = {};
-const getState = () => state;
-const setState = (newState) => Object.assign(state, newState);
-module.exports = { getState, setState };
diff --git a/test/main.test.js b/test/main.test.js
index f888631..f626d73 100644
--- a/test/main.test.js
+++ b/test/main.test.js
@@ -2,8 +2,12 @@ const assert = require('chai').assert;
 
 const { integrify } = require('../lib');
 
+const admin = require('firebase-admin');
+admin.initializeApp();
+const db = admin.firestore();
+
 describe('Error conditions', () => {
-  it('should error on bad rule', function () {
+  it('should error on bad rule', () => {
     assert.throws(
       () => integrify({ rule: 'BAD_RULE_ea8e3a2a2d3e' }),
       /Unknown rule/i
@@ -11,14 +15,93 @@ describe('Error conditions', () => {
     assert.throws(() => require('./functions-bad-rules-file'), /Unknown rule/i);
   });
 
-  it('should error on no rule or config', function () {
+  it('should error on no rule or config', () => {
     assert.throws(() => integrify(42), /Input must be rule or config/i);
   });
 
-  it('should error on absent config file', function () {
+  it('should error on absent config file', () => {
     assert.throws(
       () => require('./functions-absent-rules-file'),
       /Rules file not found/i
     );
   });
 });
+
+describe('REPLICATE_ATTRIBUTES', () => {
+  it('should replicate attributes', async () => {
+    // Create master document to replicate from
+    const masterRef = await db
+      .collection('master')
+      .add({ random: Math.random() });
+    const masterId = masterRef.id;
+
+    // Create couple of detail docs to replicate to
+    await db.collection('detail1').add({ masterId });
+    await db.collection('detail2').add({ masterId });
+
+    // Update master doc
+    const masterField1 = randstr();
+    const masterField2 = randstr();
+    await masterRef.update({ masterField1, masterField2 });
+
+    // Ensure update is reflected in detail docs
+    await assertQuerySizeEventually(
+      db
+        .collection('detail1')
+        .where('masterId', '==', masterId)
+        .where('detail1Field1', '==', masterField1),
+      1
+    );
+    await assertQuerySizeEventually(
+      db
+        .collection('detail2')
+        .where('masterId', '==', masterId)
+        .where('detail2Field1', '==', masterField1),
+      1
+    );
+
+    // Make an irrelevant update
+    await masterRef.set({ someOtherField: randstr() });
+
+    // Ensure prehook is called twice (once for each update)
+    await assertQuerySizeEventually(
+      db
+        .collection('prehooks')
+        .where(
+          'message',
+          '==',
+          '[788a32e05504] REPLICATE_ATTRIBUTES prehook was called!'
+        ),
+      2
+    );
+  });
+});
+
+// Helper functions
+function randstr() {
+  return Math.random().toString(36).substr(2);
+}
+
+function sleep(ms) {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+async function assertQuerySizeEventually(
+  query,
+  expectedResultSize,
+  log = console.log
+) {
+  log(`Asserting query result to have [${expectedResultSize}] entries ... `);
+  await sleep(1000);
+  const docs = await new Promise((res) => {
+    unsubscribe = query.onSnapshot((snap) => {
+      log(`Current result size: [${snap.size}]`);
+      if (snap.size === expectedResultSize) {
+        log('Matched!');
+        unsubscribe();
+        res(snap.docs);
+      }
+    });
+  });
+  return docs;
+}
diff --git a/test/run-tests.sh b/test/run-tests.sh
index 8fb7550..9d68cfd 100755
--- a/test/run-tests.sh
+++ b/test/run-tests.sh
@@ -9,6 +9,8 @@ rm -rf ../.nyc_output ../coverage
 
 export GCLOUD_PROJECT=dummy-project
 export FIRESTORE_EMULATOR_HOST='localhost:8080'
-npx nyc -r html -r text -r lcov firebase emulators:exec \
-  'mocha --bail --exit --jobs 1 --timeout 30s *.test.js'
-
+: ${MOCHA_TIMEOUT:=30000}
+npx \
+  nyc -r html -r text -r lcov \
+  firebase emulators:exec --ui \
+  "mocha --bail --exit --jobs 1 --timeout $MOCHA_TIMEOUT *.test.js"