diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 97eca57..9908546 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -31,4 +31,4 @@ jobs:
         run: |
           . venv/bin/activate
           mkdir -p test-reports
-          pytest -v -s --junitxml=test-reports/junit.xml --cov=client --cov-config=.coveragerc --cov-report xml
+          pytest -v -s --junitxml=test-reports/junit.xml --cov=client --cov-config=.coveragerc --cov-report xml --cov-fail-under=100
diff --git a/client/connection.py b/client/connection.py
index 0df0f20..1fd1f35 100644
--- a/client/connection.py
+++ b/client/connection.py
@@ -25,8 +25,11 @@ class ClientHosts(TypedDict):
 class Session(requests.Session):
 
     def __init__(self, *args, **kwargs):
-        if 'hostname' in kwargs:
-            self.hostname = kwargs.pop('hostname')
+        if 'hostname' not in kwargs:
+            raise ValueError('hostname is required')
+
+        self.hostname = kwargs.pop('hostname')
+
         super().__init__(*args, **kwargs)
 
     @retry
@@ -37,8 +40,8 @@ def send(self, request, **kwargs):
         return super().send(request, **kwargs)
 
     def prepare_request(self, request):
-        if self.hostname is not None:
-            request.url = f'{self.hostname}/{request.url}'
+        request.url = f'{self.hostname}/{request.url}'
+
         return super().prepare_request(request)
 
 class Connection(object):
diff --git a/tests/api/test_transactions.py b/tests/api/test_transactions.py
index fbc5412..4ffcffb 100644
--- a/tests/api/test_transactions.py
+++ b/tests/api/test_transactions.py
@@ -135,6 +135,23 @@ def test_all_unconfirmed_calls_correct_url_with_additional_params():
     assert 'limit=69' in responses.calls[0].request.url
     assert 'orderBy=timestamp.epoch' in responses.calls[0].request.url
 
+
+def test_get_unconfirmed_calls_correct_url():
+    transaction_id = '12345'
+
+    responses.add(
+      responses.GET,
+      'http://127.0.0.1:4002/api/transactions/unconfirmed/{}'.format(transaction_id),
+      json={'success': True},
+      status=200
+    )
+
+    client = ArkClient('http://127.0.0.1:4002/api')
+    client.transactions.get_unconfirmed(transaction_id)
+    assert len(responses.calls) == 1
+    assert responses.calls[0].request.url == 'http://127.0.0.1:4002/api/transactions/unconfirmed/12345'
+
+
 def test_configuration_calls_correct_url():
     responses.add(
         responses.GET,
diff --git a/tests/test_connection.py b/tests/test_connection.py
index dab0964..26dbf07 100644
--- a/tests/test_connection.py
+++ b/tests/test_connection.py
@@ -4,7 +4,7 @@
 
 import responses
 
-from client.connection import Connection
+from client.connection import Connection, Session
 from client.exceptions import ArkHTTPException
 
 
@@ -162,3 +162,31 @@ def test_http_methods_call_correct_url_with_params_and_return_correct_response(m
     assert data == {'success': True}
     assert len(responses.calls) == 1
     assert responses.calls[0].request.url == 'http://127.0.0.1:4003/spongebob?foo=bar'
+
+
+def test_session_detects_hostname_correctly():
+    session = Session(hostname="test.com")
+    assert session.hostname == "test.com"
+    assert isinstance(session, requests.Session)
+
+
+def test_session_throws_error_when_missing_hostname():
+    with pytest.raises(ValueError) as exception:
+        Session()
+
+        assert exception.value == 'hostname is required'
+
+
+def test_session_prepends_hostname_to_url():
+    responses.add(
+        responses.GET,
+        'http://test.com/spongebob',
+        json={'success': True},
+        status=200
+    )
+
+    session = Session(hostname="http://test.com")
+
+    session.get('spongebob')
+    assert len(responses.calls) == 1
+    assert responses.calls[0].request.url == 'http://test.com/spongebob'