Add max file size check when uploading a letter

app/main/views/uploads.py

@@ -9,6 +9,8 @@ from app.main import main
 from app.main.forms import PDFUploadForm
 from app.utils import user_has_permissions
 
+MAX_FILE_UPLOAD_SIZE = 2 * 1024 * 1024  # 2MB
+
 
 @main.route("/services/<service_id>/uploads")
 @user_has_permissions('send_messages')
@@ -29,6 +31,10 @@ def upload_letter(service_id):
             flash('Your file has failed the virus check', 'dangerous')
             return render_template('views/uploads/choose-file.html', form=form), 400
 
+        if len(pdf_file_bytes) > MAX_FILE_UPLOAD_SIZE:
+            flash('Your file must be smaller than 2MB', 'dangerous')
+            return render_template('views/uploads/choose-file.html', form=form), 400
+
         upload_id = uuid.uuid4()
 
         return redirect(

tests/app/main/views/test_uploads.py

@@ -76,6 +76,20 @@ def test_post_upload_letter_shows_error_when_file_contains_virus(mocker, client_
     assert normalize_spaces(page.select('.banner-dangerous')[0].text) == 'Your file has failed the virus check'
 
 
+def test_post_choose_upload_file_when_file_is_too_big(mocker, client_request):
+    mocker.patch('app.main.views.uploads.antivirus_client.scan', return_value=True)
+
+    with open('tests/test_pdf_files/big.pdf', 'rb') as file:
+        page = client_request.post(
+            'main.upload_letter',
+            service_id=SERVICE_ONE_ID,
+            _data={'file': file},
+            _expected_status=400
+        )
+    assert page.find('h1').text == 'Upload a letter'
+    assert normalize_spaces(page.select('.banner-dangerous')[0].text) == 'Your file must be smaller than 2MB'
+
+
 def test_uploaded_letter_preview(client_request):
     page = client_request.get(
         'main.uploaded_letter_preview',