diff --git a/src/test/FileUploader.spec.ts b/src/test/FileUploader.spec.ts
index 8f12ba3..b76b527 100644
--- a/src/test/FileUploader.spec.ts
+++ b/src/test/FileUploader.spec.ts
@@ -1,81 +1,5 @@
 import { FileUploader } from '../FileUploader'
 import { UploadFile } from '../types'
-;(global as any).fetch = jest.fn().mockImplementation(() =>
-  Promise.resolve({
-    text: () => Promise.resolve(sampleResponse)
-  })
-)
-
-it('should upload successfully', async (done) => {
-  const fileUploader = new FileUploader(
-    '/sample/apploc',
-    'https://sample.server.com',
-    '/jobs/path',
-    null,
-    null
-  )
-
-  const sasJob = 'test/upload'
-  const files: UploadFile[] = [
-    {
-      file: new File([''], 'testfile'),
-      fileName: 'testfile'
-    }
-  ]
-  const params = { table: 'libtable' }
-
-  fileUploader.uploadFile(sasJob, files, params).then((res: any) => {
-    if (JSON.stringify(res) === JSON.stringify(JSON.parse(sampleResponse)))
-      done()
-  })
-})
-
-it('should throw no files error', async (done) => {
-  const fileUploader = new FileUploader(
-    '/sample/apploc',
-    'https://sample.server.com',
-    '/jobs/path',
-    null,
-    null
-  )
-
-  const sasJob = 'test/upload'
-  const files: UploadFile[] = []
-  const params = { table: 'libtable' }
-
-  fileUploader.uploadFile(sasJob, files, params).then(
-    (res: any) => {},
-    (err: any) => {
-      if (err.error.message === 'At least one file must be provided.') done()
-    }
-  )
-})
-
-it('should throw no sasJob error', async (done) => {
-  const fileUploader = new FileUploader(
-    '/sample/apploc',
-    'https://sample.server.com',
-    '/jobs/path',
-    null,
-    null
-  )
-
-  const sasJob = ''
-  const files: UploadFile[] = [
-    {
-      file: new File([''], 'testfile'),
-      fileName: 'testfile'
-    }
-  ]
-  const params = { table: 'libtable' }
-
-  fileUploader.uploadFile(sasJob, files, params).then(
-    (res: any) => {},
-    (err: any) => {
-      if (err.error.message === 'sasJob must be provided.') done()
-    }
-  )
-})
 
 const sampleResponse = `{
   "SYSUSERID": "cas",
@@ -86,3 +10,187 @@ const sampleResponse = `{
   "SYSJOBID" : "117382",
   "SYSWARNINGTEXT" : ""
 }`
+
+describe('FileUploader', () => {
+  let originalFetch: any
+
+  beforeAll(() => {
+    originalFetch = (global as any).fetch
+  })
+
+  beforeEach(() => {
+    ;(global as any).fetch = jest.fn().mockImplementation(() =>
+      Promise.resolve({
+        text: () => Promise.resolve(sampleResponse)
+      })
+    )
+  })
+
+  afterAll(() => {
+    ;(global as any).fetch = originalFetch
+  })
+
+  it('should upload successfully', async (done) => {
+    const fileUploader = new FileUploader(
+      '/sample/apploc',
+      'https://sample.server.com',
+      '/jobs/path',
+      null,
+      null
+    )
+
+    const sasJob = 'test/upload'
+    const files: UploadFile[] = [
+      {
+        file: new File([''], 'testfile'),
+        fileName: 'testfile'
+      }
+    ]
+    const params = { table: 'libtable' }
+
+    fileUploader.uploadFile(sasJob, files, params).then((res: any) => {
+      expect(JSON.stringify(res)).toEqual(
+        JSON.stringify(JSON.parse(sampleResponse))
+      )
+      done()
+    })
+  })
+
+  it('should an error when no files are provided', async (done) => {
+    const fileUploader = new FileUploader(
+      '/sample/apploc',
+      'https://sample.server.com',
+      '/jobs/path',
+      null,
+      null
+    )
+
+    const sasJob = 'test/upload'
+    const files: UploadFile[] = []
+    const params = { table: 'libtable' }
+
+    fileUploader.uploadFile(sasJob, files, params).catch((err: any) => {
+      expect(err.error.message).toEqual('At least one file must be provided.')
+      done()
+    })
+  })
+
+  it('should throw an error when no sasJob is provided', async (done) => {
+    const fileUploader = new FileUploader(
+      '/sample/apploc',
+      'https://sample.server.com',
+      '/jobs/path',
+      null,
+      null
+    )
+
+    const sasJob = ''
+    const files: UploadFile[] = [
+      {
+        file: new File([''], 'testfile'),
+        fileName: 'testfile'
+      }
+    ]
+    const params = { table: 'libtable' }
+
+    fileUploader.uploadFile(sasJob, files, params).catch((err: any) => {
+      expect(err.error.message).toEqual('sasJob must be provided.')
+      done()
+    })
+  })
+
+  it('should throw an error when login is required', async (done) => {
+    ;(global as any).fetch = jest.fn().mockImplementation(() =>
+      Promise.resolve({
+        text: () => Promise.resolve('<form action="Logon">')
+      })
+    )
+
+    const fileUploader = new FileUploader(
+      '/sample/apploc',
+      'https://sample.server.com',
+      '/jobs/path',
+      null,
+      null
+    )
+
+    const sasJob = 'test'
+    const files: UploadFile[] = [
+      {
+        file: new File([''], 'testfile'),
+        fileName: 'testfile'
+      }
+    ]
+    const params = { table: 'libtable' }
+
+    fileUploader.uploadFile(sasJob, files, params).catch((err: any) => {
+      expect(err.error.message).toEqual(
+        'You must be logged in to upload a file.'
+      )
+      done()
+    })
+  })
+
+  it('should throw an error when invalid JSON is returned by the server', async (done) => {
+    ;(global as any).fetch = jest.fn().mockImplementation(() =>
+      Promise.resolve({
+        text: () => Promise.resolve('{invalid: "json"')
+      })
+    )
+
+    const fileUploader = new FileUploader(
+      '/sample/apploc',
+      'https://sample.server.com',
+      '/jobs/path',
+      null,
+      null
+    )
+
+    const sasJob = 'test'
+    const files: UploadFile[] = [
+      {
+        file: new File([''], 'testfile'),
+        fileName: 'testfile'
+      }
+    ]
+    const params = { table: 'libtable' }
+
+    fileUploader.uploadFile(sasJob, files, params).catch((err: any) => {
+      expect(err.error.message).toEqual(
+        'Error while parsing json from upload response.'
+      )
+      done()
+    })
+  })
+
+  it('should throw an error when the server request fails', async (done) => {
+    ;(global as any).fetch = jest.fn().mockImplementation(() =>
+      Promise.resolve({
+        text: () => Promise.reject('{message: "Server error"}')
+      })
+    )
+
+    const fileUploader = new FileUploader(
+      '/sample/apploc',
+      'https://sample.server.com',
+      '/jobs/path',
+      null,
+      null
+    )
+
+    const sasJob = 'test'
+    const files: UploadFile[] = [
+      {
+        file: new File([''], 'testfile'),
+        fileName: 'testfile'
+      }
+    ]
+    const params = { table: 'libtable' }
+
+    fileUploader.uploadFile(sasJob, files, params).catch((err: any) => {
+      expect(err.error.message).toEqual('Upload request failed.')
+
+      done()
+    })
+  })
+})