diff --git a/tests/test_s3/test_s3.py b/tests/test_s3/test_s3.py
index 07137bcfa..6e339abb6 100644
--- a/tests/test_s3/test_s3.py
+++ b/tests/test_s3/test_s3.py
@@ -524,7 +524,7 @@ def test_post_to_bucket():
 
     requests.post("https://foobar.s3.amazonaws.com/", {
         'key': 'the-key',
-        'file': b'nothing'
+        'file': 'nothing'
     })
 
     bucket.get_key('the-key').get_contents_as_string().should.equal(b'nothing')
@@ -538,7 +538,7 @@ def test_post_with_metadata_to_bucket():
 
     requests.post("https://foobar.s3.amazonaws.com/", {
         'key': 'the-key',
-        'file': b'nothing',
+        'file': 'nothing',
         'x-amz-meta-test': 'metadata'
     })
 
diff --git a/tests/test_s3/test_server.py b/tests/test_s3/test_server.py
index 934dd5a42..9c8252a04 100644
--- a/tests/test_s3/test_server.py
+++ b/tests/test_s3/test_server.py
@@ -72,7 +72,7 @@ def test_s3_server_post_to_bucket():
 
     test_client.post('/', "https://tester.localhost:5000/", data={
         'key': 'the-key',
-        'file': b'nothing'
+        'file': 'nothing'
     })
 
     res = test_client.get('/the-key', 'http://tester.localhost:5000/')
diff --git a/tests/test_s3bucket_path/test_bucket_path_server.py b/tests/test_s3bucket_path/test_bucket_path_server.py
index 604adc289..434110e87 100644
--- a/tests/test_s3bucket_path/test_bucket_path_server.py
+++ b/tests/test_s3bucket_path/test_bucket_path_server.py
@@ -73,7 +73,7 @@ def test_s3_server_post_to_bucket():
 
     test_client.post('/foobar2', "https://localhost:5000/", data={
         'key': 'the-key',
-        'file': b'nothing'
+        'file': 'nothing'
     })
 
     res = test_client.get('/foobar2/the-key', 'http://localhost:5000/')
@@ -89,7 +89,7 @@ def test_s3_server_put_ipv6():
 
     test_client.post('/foobar2', "https://[::]:5000/", data={
         'key': 'the-key',
-        'file': b'nothing'
+        'file': 'nothing'
     })
 
     res = test_client.get('/foobar2/the-key', 'http://[::]:5000/')
@@ -105,7 +105,7 @@ def test_s3_server_put_ipv4():
 
     test_client.post('/foobar2', "https://127.0.0.1:5000/", data={
         'key': 'the-key',
-        'file': b'nothing'
+        'file': 'nothing'
     })
 
     res = test_client.get('/foobar2/the-key', 'http://127.0.0.1:5000/')
diff --git a/tests/test_s3bucket_path/test_s3bucket_path.py b/tests/test_s3bucket_path/test_s3bucket_path.py
index 58ae4db6f..21d786c61 100644
--- a/tests/test_s3bucket_path/test_s3bucket_path.py
+++ b/tests/test_s3bucket_path/test_s3bucket_path.py
@@ -198,7 +198,7 @@ def test_post_to_bucket():
 
     requests.post("https://s3.amazonaws.com/foobar", {
         'key': 'the-key',
-        'file': b'nothing'
+        'file': 'nothing'
     })
 
     bucket.get_key('the-key').get_contents_as_string().should.equal(b'nothing')
@@ -212,7 +212,7 @@ def test_post_with_metadata_to_bucket():
 
     requests.post("https://s3.amazonaws.com/foobar", {
         'key': 'the-key',
-        'file': b'nothing',
+        'file': 'nothing',
         'x-amz-meta-test': 'metadata'
     })