diff --git a/src/rybak/jinja.py b/src/rybak/jinja.py
index 6fdefba..bb02651 100644
--- a/src/rybak/jinja.py
+++ b/src/rybak/jinja.py
@@ -32,7 +32,7 @@ def __init__(
         else:
             if keep_trailing_newline is not None:
                 self._env = environment.overlay()
-                self._env.keep_trailing_newline = self._keep_trailing_newline
+                self._env.keep_trailing_newline = keep_trailing_newline
 
     def render_str(self, template: str, data: TemplateData, loop_over: Optional[LoopOverFn] = None) -> str:
         env = self._env.overlay()
diff --git a/tests/test_jinja.py b/tests/test_jinja.py
new file mode 100644
index 0000000..1dc86e9
--- /dev/null
+++ b/tests/test_jinja.py
@@ -0,0 +1,34 @@
+import pytest
+from jinja2 import Environment, FileSystemLoader
+from rybak.jinja import JinjaAdapter
+
+
+def test_jinja_init_keep_newlines():
+    env = Environment(loader=FileSystemLoader('-path-'))
+    adapter = JinjaAdapter(env)
+
+    assert adapter._env.keep_trailing_newline is True
+
+
+def test_jinja_init_keep_newlines_false():
+    env = Environment(loader=FileSystemLoader('-path-'))
+    adapter = JinjaAdapter(env, keep_trailing_newline=False)
+
+    assert adapter._env.keep_trailing_newline is False
+
+
+def test_jinja_loader():
+    loader = FileSystemLoader('-path-')
+    adapter = JinjaAdapter(loader=loader)
+
+    assert adapter._env.loader == loader
+
+
+def test_jinja_env_loader_error():
+    with pytest.raises(ValueError):
+        JinjaAdapter(environment=Environment(), loader=FileSystemLoader('-path-'))
+
+
+def test_jinja_no_env_loader_error():
+    with pytest.raises(ValueError):
+        JinjaAdapter()