diff --git a/test/functional/replicaset_mock.test.js b/test/functional/replicaset_mock.test.js
deleted file mode 100644
index 8c2665ac398..00000000000
--- a/test/functional/replicaset_mock.test.js
+++ /dev/null
@@ -1,142 +0,0 @@
-'use strict';
-const { expect } = require('chai');
-const mock = require('../tools/mongodb-mock/index');
-const { ObjectId } = require('bson');
-const { Logger } = require('../../src/logger');
-const { isHello } = require('../../src/utils');
-
-const test = {};
-describe('ReplSet (mocks)', function () {
-  afterEach(() => mock.cleanup());
-  beforeEach(() => {
-    // Default message fields
-    const defaultFields = Object.assign({}, mock.HELLO, {
-      msg: 'isdbgrid'
-    });
-
-    // Default message fields
-    const defaultRSFields = Object.assign({}, mock.HELLO, {
-      setName: 'rs',
-      setVersion: 1,
-      electionId: new ObjectId(),
-      hosts: ['localhost:32000', 'localhost:32001', 'localhost:32002'],
-      arbiters: ['localhost:32002']
-    });
-
-    // Primary server states
-    const serverIsPrimary = [Object.assign({}, defaultFields), Object.assign({}, defaultRSFields)];
-
-    return Promise.all([mock.createServer(), mock.createServer()]).then(servers => {
-      test.mongos1 = servers[0];
-      test.mongos2 = servers[1];
-
-      test.mongos1.setMessageHandler(request => {
-        var doc = request.document;
-        if (isHello(doc)) {
-          request.reply(serverIsPrimary[0]);
-        } else if (doc.insert) {
-          request.reply({ ok: 1, n: doc.documents, lastOp: new Date() });
-        } else if (doc.endSessions) {
-          request.reply({ ok: 1 });
-        }
-      });
-
-      test.mongos2.setMessageHandler(request => {
-        var doc = request.document;
-        if (isHello(doc)) {
-          request.reply(serverIsPrimary[1]);
-        } else if (doc.insert) {
-          request.reply({ ok: 1, n: doc.documents, lastOp: new Date() });
-        } else if (doc.endSessions) {
-          request.reply({ ok: 1 });
-        }
-      });
-    });
-  });
-
-  it('Should correctly print warning when non mongos proxy passed in seed list', {
-    metadata: {
-      requires: {
-        generators: true,
-        topology: 'single'
-      }
-    },
-
-    test: function (done) {
-      var configuration = this.configuration;
-      var logger = Logger.currentLogger();
-      Logger.setLevel('warn');
-      Logger.setCurrentLogger(function (msg, state) {
-        expect(state.type).to.equal('warn');
-        expect(state.message).to.equal(
-          `expected mongos proxy, but found replicaset member mongod for server ${test.mongos2.uri()}`
-        );
-      });
-
-      const client = configuration.newClient(
-        `mongodb://${test.mongos1.uri()},${test.mongos2.uri()}/test`
-      );
-      client.connect(function (err, client) {
-        Logger.setCurrentLogger(logger);
-        Logger.reset();
-        expect(err).to.not.exist;
-
-        client.close(done);
-      });
-    }
-  });
-
-  // TODO(NODE-3664): Unskip
-  it.skip('Should correctly print warning and error when no mongos proxies in seed list', {
-    metadata: {
-      requires: {
-        generators: true,
-        topology: 'single'
-      }
-    },
-
-    test: function (done) {
-      var configuration = this.configuration;
-      var warnings = [];
-      var logger = Logger.currentLogger();
-      Logger.setLevel('warn');
-      Logger.setCurrentLogger(function (msg, state) {
-        expect(state.type).to.equal('warn');
-        warnings.push(state);
-      });
-
-      const client = configuration.newClient(
-        `mongodb://${test.mongos1.uri()},${test.mongos2.uri()}/test`
-      );
-
-      client.connect(function (err, client) {
-        Logger.setCurrentLogger(logger);
-        Logger.reset();
-
-        // Assert all warnings
-        expect(warnings[0].message).to.equal(
-          `expected mongos proxy, but found replicaset member mongod for server ${test.mongos1.uri()}`
-        );
-
-        expect(warnings[1].message).to.equal(
-          `expected mongos proxy, but found replicaset member mongod for server ${test.mongos2.uri()}`
-        );
-
-        expect(warnings[2].message).to.equal(
-          'no mongos proxies found in seed list, did you mean to connect to a replicaset'
-        );
-
-        expect(warnings[3].message).to.equal(
-          'seed list contains no mongos proxies, replicaset connections requires the parameter replicaSet to be supplied in the URI or options object, mongodb://server:port/db?replicaSet=name'
-        );
-
-        // Assert error
-        expect(err.message).to.equal(
-          'seed list contains no mongos proxies, replicaset connections requires the parameter replicaSet to be supplied in the URI or options object, mongodb://server:port/db?replicaSet=name'
-        );
-
-        client.close(done);
-      });
-    }
-  });
-});
diff --git a/test/functional/saslprep.test.js b/test/integration/auth/saslprep.test.js
similarity index 96%
rename from test/functional/saslprep.test.js
rename to test/integration/auth/saslprep.test.js
index f8685d09c64..49065834131 100644
--- a/test/functional/saslprep.test.js
+++ b/test/integration/auth/saslprep.test.js
@@ -1,7 +1,6 @@
 'use strict';
 
-const setupDatabase = require('./shared').setupDatabase;
-const withClient = require('./shared').withClient;
+const { setupDatabase, withClient } = require('../shared');
 
 describe('SASLPrep', function () {
   // Step 4
diff --git a/test/functional/scram.test.js b/test/integration/auth/scram_sha_1.test.js
similarity index 94%
rename from test/functional/scram.test.js
rename to test/integration/auth/scram_sha_1.test.js
index 860bff09e5a..ae159b80af0 100644
--- a/test/functional/scram.test.js
+++ b/test/integration/auth/scram_sha_1.test.js
@@ -1,9 +1,9 @@
 'use strict';
-var test = require('./shared').assert;
-var setupDatabase = require('./shared').setupDatabase;
-const { MongoClient } = require('../../src');
+const { MongoClient } = require('../../../src');
 const { expect } = require('chai');
 
+const { assert: test, setupDatabase } = require('../shared');
+
 describe('SCRAM', function () {
   before(function () {
     return setupDatabase(this.configuration);
diff --git a/test/functional/scram_sha_256.test.js b/test/integration/auth/scram_sha_256.test.js
similarity index 97%
rename from test/functional/scram_sha_256.test.js
rename to test/integration/auth/scram_sha_256.test.js
index ae66f226f03..83d4ac1f455 100644
--- a/test/functional/scram_sha_256.test.js
+++ b/test/integration/auth/scram_sha_256.test.js
@@ -2,10 +2,10 @@
 
 const sinon = require('sinon');
 const { expect } = require('chai');
-const { Connection } = require('../../src/cmap/connection');
-const { ScramSHA256 } = require('../../src/cmap/auth/scram');
-const { setupDatabase, withClient } = require('./shared');
-const { LEGACY_HELLO_COMMAND } = require('../../src/constants');
+const { Connection } = require('../../../src/cmap/connection');
+const { ScramSHA256 } = require('../../../src/cmap/auth/scram');
+const { setupDatabase, withClient } = require('../shared');
+const { LEGACY_HELLO_COMMAND } = require('../../../src/constants');
 
 describe('SCRAM-SHA-256 auth', function () {
   const test = {};
diff --git a/test/functional/ssl_x509_connect.test.js b/test/integration/auth/ssl_x509_connect.test.js
similarity index 99%
rename from test/functional/ssl_x509_connect.test.js
rename to test/integration/auth/ssl_x509_connect.test.js
index bc25874d258..fb3ef69f3e0 100644
--- a/test/functional/ssl_x509_connect.test.js
+++ b/test/integration/auth/ssl_x509_connect.test.js
@@ -1,10 +1,9 @@
 'use strict';
-var fs = require('fs');
-var f = require('util').format;
-var test = require('./shared').assert;
-var setupDatabase = require('./shared').setupDatabase;
+const fs = require('fs');
+const { format: f } = require('util');
+const { test, setupDatabase } = require('../shared');
 const { expect } = require('chai');
-const { MongoClient } = require('../../src');
+const { MongoClient } = require('../../../src');
 
 describe('SSL (x509)', function () {
   before(function () {
diff --git a/test/functional/custom_pk.test.js b/test/integration/crud/pk_factory.test.js
similarity index 89%
rename from test/functional/custom_pk.test.js
rename to test/integration/crud/pk_factory.test.js
index aec25f9863c..68d7b98ab24 100644
--- a/test/functional/custom_pk.test.js
+++ b/test/integration/crud/pk_factory.test.js
@@ -1,9 +1,9 @@
 'use strict';
 const { expect } = require('chai');
-var setupDatabase = require('./shared').setupDatabase;
-const { ObjectId } = require('../../src');
+var setupDatabase = require('../../functional/shared').setupDatabase;
+const { ObjectId } = require('../../../src');
 
-describe('Custom PK', function () {
+describe('PkFactory', function () {
   before(function () {
     return setupDatabase(this.configuration);
   });
diff --git a/test/functional/promote_buffers.test.js b/test/integration/node-specific/bson-options/promote_buffers.test.js
similarity index 98%
rename from test/functional/promote_buffers.test.js
rename to test/integration/node-specific/bson-options/promote_buffers.test.js
index ea2aaa44392..32ca62e911c 100644
--- a/test/functional/promote_buffers.test.js
+++ b/test/integration/node-specific/bson-options/promote_buffers.test.js
@@ -1,7 +1,7 @@
 'use strict';
-var test = require('./shared').assert;
 const { expect } = require('chai');
-var setupDatabase = require('./shared').setupDatabase;
+
+const { assert: test, setupDatabase } = require('../../shared');
 
 describe('Promote Buffers', function () {
   before(function () {
diff --git a/test/functional/promote_values.test.js b/test/integration/node-specific/bson-options/promote_values.test.js
similarity index 98%
rename from test/functional/promote_values.test.js
rename to test/integration/node-specific/bson-options/promote_values.test.js
index c301a1c497c..d1cd7ef2c29 100644
--- a/test/functional/promote_values.test.js
+++ b/test/integration/node-specific/bson-options/promote_values.test.js
@@ -1,8 +1,7 @@
 'use strict';
-var test = require('./shared').assert;
 const { expect } = require('chai');
-var setupDatabase = require('./shared').setupDatabase;
-const { Long, Int32, Double } = require('../../src');
+const { Long, Int32, Double } = require('../../../../src');
+const { assert: test, setupDatabase } = require('../../shared');
 
 describe('Promote Values', function () {
   before(function () {
diff --git a/test/functional/raw.test.js b/test/integration/node-specific/bson-options/raw.test.js
similarity index 98%
rename from test/functional/raw.test.js
rename to test/integration/node-specific/bson-options/raw.test.js
index c146d019d65..dcbd3b5a19c 100644
--- a/test/functional/raw.test.js
+++ b/test/integration/node-specific/bson-options/raw.test.js
@@ -1,5 +1,5 @@
 'use strict';
-const { assert: test, setupDatabase } = require('./shared');
+const { assert: test, setupDatabase } = require('../../shared');
 const { Buffer } = require('buffer');
 const { expect } = require('chai');
 
diff --git a/test/functional/sharding_connection.test.js b/test/integration/server-discovery-and-monitoring/sharding_connection.test.js
similarity index 82%
rename from test/functional/sharding_connection.test.js
rename to test/integration/server-discovery-and-monitoring/sharding_connection.test.js
index 5143701a173..94199d18217 100644
--- a/test/functional/sharding_connection.test.js
+++ b/test/integration/server-discovery-and-monitoring/sharding_connection.test.js
@@ -1,8 +1,8 @@
 'use strict';
 
-const { withClient, setupDatabase } = require('./shared');
+const { withClient, setupDatabase } = require('../shared');
 const { expect } = require('chai');
-const { TopologyType } = require('../../src/sdam/common');
+const { TopologyType } = require('../../../src/sdam/common');
 
 describe('Sharding (Connection)', function () {
   before(function () {
diff --git a/test/functional/readpreference.test.js b/test/integration/server-selection/readpreference.test.js
similarity index 98%
rename from test/functional/readpreference.test.js
rename to test/integration/server-selection/readpreference.test.js
index 3174642566f..e57a3cdb2c6 100644
--- a/test/functional/readpreference.test.js
+++ b/test/integration/server-selection/readpreference.test.js
@@ -1,13 +1,11 @@
 'use strict';
 
-const test = require('./shared').assert;
-const setupDatabase = require('./shared').setupDatabase;
-const withMonitoredClient = require('./shared').withMonitoredClient;
-const { ReadPreference, Topology } = require('../../src');
-const { withClient } = require('./shared');
+const { ReadPreference, Topology } = require('../../../src');
 const chai = require('chai');
 chai.use(require('chai-subset'));
 
+const { assert: test, setupDatabase, withClient, withMonitoredClient } = require('../shared');
+
 const expect = chai.expect;
 
 describe('ReadPreference', function () {