diff --git a/test/basename.test.js b/test/basename.test.js
new file mode 100644
index 0000000..0fb4a69
--- /dev/null
+++ b/test/basename.test.js
@@ -0,0 +1,28 @@
+'use strict'
+
+const { test } = require('tap')
+const basename = require('../lib/utils/basename')
+
+test('basename', (t) => {
+  const testCases = [
+    { description: 'returns an empty string if the path is not a string', path: {}, expected: '' },
+    { description: 'returns an empty string if the path includes a \' and the char after is a .', path: 'path\\.', expected: '' },
+    { description: 'returns an empty string if the path includes a / and the char after is a .', path: 'path/.', expected: '' },
+    { description: 'returns an empty string if the path includes a \' and the chars after are a ..', path: 'path\\..', expected: '' },
+    { description: 'returns an empty string if the path includes a / and the chars after are a ..', path: 'path/..', expected: '' },
+    { description: 'returns the path if the path includes a \' and the rest is anything other than dots', path: 'path\\subpath', expected: 'subpath' },
+    { description: 'returns the path if the path includes a / and the rest is anything other than dots', path: 'path/subpath', expected: 'subpath' },
+    { description: 'returns an empty string if the path is a .', path: '.', expected: '' },
+    { description: 'returns an empty string if the path is a ..', path: '..', expected: '' },
+    { description: 'returns the path if the path is anything other than dots', path: 'subpath', expected: 'subpath' }
+  ]
+
+  t.plan(testCases.length)
+
+  testCases.forEach((testCase, index) => {
+    t.test(testCase.description, t => {
+      t.plan(1)
+      t.equal(basename(testCase.path), testCase.expected, `Test case ${index + 1}`)
+    })
+  })
+})
diff --git a/test/busboy-emit.test.js b/test/busboy-emit.test.js
new file mode 100644
index 0000000..1e539ab
--- /dev/null
+++ b/test/busboy-emit.test.js
@@ -0,0 +1,17 @@
+'use strict'
+
+const Busboy = require('../lib/main')
+const { test } = require('tap')
+
+test('busboy, emit', t => {
+  t.plan(1)
+
+  t.test('returns undefined when the event is called a second time and the busboy was already finished', t => {
+    const busboy = new Busboy({ headers: { 'content-type': 'application/x-www-form-urlencoded' } })
+    busboy._finished = true
+    busboy.emit('finish')
+
+    t.equal(busboy.emit('finish'), undefined)
+    t.end()
+  })
+})
diff --git a/test/dicer-write.test.js b/test/dicer-write.test.js
new file mode 100644
index 0000000..f270fa3
--- /dev/null
+++ b/test/dicer-write.test.js
@@ -0,0 +1,19 @@
+'use strict'
+
+const { test } = require('tap')
+const { Dicer } = require('../lib/main')
+
+test('dicer _write method', t => {
+  t.plan(1)
+
+  t.test('calls the callback cb() when headerFirst is set and all the data have been written', t => {
+    t.plan(1)
+    const dicer = new Dicer({ headerFirst: true })
+
+    dicer._write(Buffer.from('Content-Type: text/plain'), null, () => {
+      dicer._write(Buffer.from('Content-Type: text/plain'), null, () => {
+        t.pass('write method called')
+      })
+    })
+  })
+})
diff --git a/test/multipart-constructor.test.js b/test/multipart-constructor.test.js
new file mode 100644
index 0000000..87aaad1
--- /dev/null
+++ b/test/multipart-constructor.test.js
@@ -0,0 +1,16 @@
+'use strict'
+
+const Multipart = require('../lib/types/multipart')
+const Busboy = require('../lib/main')
+const { test } = require('tap')
+
+test('multipart constructor', t => {
+  t.plan(1)
+
+  t.test('throws if the boundary is not a string', t => {
+    const busboy = new Busboy({ headers: { 'content-type': 'application/x-www-form-urlencoded' } })
+
+    t.throws(() => new Multipart(busboy, { boundary: 123 }), new Error('Multipart: Boundary not found'))
+    t.end()
+  })
+})