diff --git a/flask_admin/tests/sqla/test_basic.py b/flask_admin/tests/sqla/test_basic.py
index 0478fe287..b0fb2f348 100644
--- a/flask_admin/tests/sqla/test_basic.py
+++ b/flask_admin/tests/sqla/test_basic.py
@@ -2645,75 +2645,76 @@ def test_export_csv(app, db, admin):
 
 
 def test_string_null_behavior(app, db, admin):
-    class StringTestModel(db.Model):
-        id = db.Column(db.Integer, primary_key=True)
-        test_no = db.Column(db.Integer, nullable=False)
-        string_field = db.Column(db.String)
-        string_field_nonull = db.Column(db.String, nullable=False)
-        string_field_nonull_default = db.Column(db.String, nullable=False, default='')
-        text_field = db.Column(db.Text)
-        text_field_nonull = db.Column(db.Text, nullable=False)
-        text_field_nonull_default = db.Column(db.Text, nullable=False, default='')
+    with app.app_context():
+        class StringTestModel(db.Model):
+            id = db.Column(db.Integer, primary_key=True)
+            test_no = db.Column(db.Integer, nullable=False)
+            string_field = db.Column(db.String)
+            string_field_nonull = db.Column(db.String, nullable=False)
+            string_field_nonull_default = db.Column(db.String, nullable=False, default='')
+            text_field = db.Column(db.Text)
+            text_field_nonull = db.Column(db.Text, nullable=False)
+            text_field_nonull_default = db.Column(db.Text, nullable=False, default='')
 
-    db.create_all()
+        db.create_all()
 
-    view = CustomModelView(StringTestModel, db.session)
-    admin.add_view(view)
+        view = CustomModelView(StringTestModel, db.session)
+        admin.add_view(view)
 
-    client = app.test_client()
+        client = app.test_client()
 
-    valid_params = {
-        "test_no": 1,
-        "string_field_nonull": STRING_CONSTANT,
-        "text_field_nonull": STRING_CONSTANT,
-    }
-    rv = client.post('/admin/stringtestmodel/new/',
-                     data=valid_params)
-    assert rv.status_code == 302
-
-    # Assert on defaults
-    valid_inst = db.session.query(StringTestModel).filter(StringTestModel.test_no == 1).one()
-    assert valid_inst.string_field is None
-    assert valid_inst.string_field_nonull == STRING_CONSTANT
-    assert valid_inst.string_field_nonull_default == ''
-    assert valid_inst.text_field is None
-    assert valid_inst.text_field_nonull == STRING_CONSTANT
-    assert valid_inst.text_field_nonull_default == ''
-
-    # Assert that nulls are caught on the non-null fields
-    invalid_string_field = {
-        "test_no": 2,
-        "string_field_nonull": None,
-        "text_field_nonull": STRING_CONSTANT,
-    }
-    rv = client.post('/admin/stringtestmodel/new/',
-                     data=invalid_string_field)
-    assert rv.status_code == 200
-    assert b'This field is required.' in rv.data
-    assert db.session.query(StringTestModel).filter(StringTestModel.test_no == 2).all() == []
-
-    invalid_text_field = {
-        "test_no": 3,
-        "string_field_nonull": STRING_CONSTANT,
-        "text_field_nonull": None,
-    }
-    rv = client.post('/admin/stringtestmodel/new/',
-                     data=invalid_text_field)
-    assert rv.status_code == 200
-    assert b'This field is required.' in rv.data
-    assert db.session.query(StringTestModel).filter(StringTestModel.test_no == 3).all() == []
-
-    # Assert that empty strings are converted to None on nullable fields.
-    empty_strings = {
-        "test_no": 4,
-        "string_field": "",
-        "text_field": "",
-        "string_field_nonull": STRING_CONSTANT,
-        "text_field_nonull": STRING_CONSTANT,
-    }
-    rv = client.post('/admin/stringtestmodel/new/',
-                     data=empty_strings)
-    assert rv.status_code == 302
-    empty_string_inst = db.session.query(StringTestModel).filter(StringTestModel.test_no == 4).one()
-    assert empty_string_inst.string_field is None
-    assert empty_string_inst.text_field is None
+        valid_params = {
+            "test_no": 1,
+            "string_field_nonull": STRING_CONSTANT,
+            "text_field_nonull": STRING_CONSTANT,
+        }
+        rv = client.post('/admin/stringtestmodel/new/',
+                         data=valid_params)
+        assert rv.status_code == 302
+
+        # Assert on defaults
+        valid_inst = db.session.query(StringTestModel).filter(StringTestModel.test_no == 1).one()
+        assert valid_inst.string_field is None
+        assert valid_inst.string_field_nonull == STRING_CONSTANT
+        assert valid_inst.string_field_nonull_default == ''
+        assert valid_inst.text_field is None
+        assert valid_inst.text_field_nonull == STRING_CONSTANT
+        assert valid_inst.text_field_nonull_default == ''
+
+        # Assert that nulls are caught on the non-null fields
+        invalid_string_field = {
+            "test_no": 2,
+            "string_field_nonull": None,
+            "text_field_nonull": STRING_CONSTANT,
+        }
+        rv = client.post('/admin/stringtestmodel/new/',
+                         data=invalid_string_field)
+        assert rv.status_code == 200
+        assert b'This field is required.' in rv.data
+        assert db.session.query(StringTestModel).filter(StringTestModel.test_no == 2).all() == []
+
+        invalid_text_field = {
+            "test_no": 3,
+            "string_field_nonull": STRING_CONSTANT,
+            "text_field_nonull": None,
+        }
+        rv = client.post('/admin/stringtestmodel/new/',
+                         data=invalid_text_field)
+        assert rv.status_code == 200
+        assert b'This field is required.' in rv.data
+        assert db.session.query(StringTestModel).filter(StringTestModel.test_no == 3).all() == []
+
+        # Assert that empty strings are converted to None on nullable fields.
+        empty_strings = {
+            "test_no": 4,
+            "string_field": "",
+            "text_field": "",
+            "string_field_nonull": STRING_CONSTANT,
+            "text_field_nonull": STRING_CONSTANT,
+        }
+        rv = client.post('/admin/stringtestmodel/new/',
+                         data=empty_strings)
+        assert rv.status_code == 302
+        empty_string_inst = db.session.query(StringTestModel).filter(StringTestModel.test_no == 4).one()
+        assert empty_string_inst.string_field is None
+        assert empty_string_inst.text_field is None