diff --git a/pr_agent/algo/__init__.py b/pr_agent/algo/__init__.py
index 23c9795b..a2b35e71 100644
--- a/pr_agent/algo/__init__.py
+++ b/pr_agent/algo/__init__.py
@@ -64,10 +64,13 @@ MAX_TOKENS = {
     'vertex_ai/gemini-1.5-flash': 1048576,
     'vertex_ai/gemini-2.0-flash': 1048576,
     'vertex_ai/gemini-2.5-flash-preview-04-17': 1048576,
+    'vertex_ai/gemini-2.5-flash-preview-05-20': 1048576,
     'vertex_ai/gemma2': 8200,
     'gemini/gemini-1.5-pro': 1048576,
     'gemini/gemini-1.5-flash': 1048576,
     'gemini/gemini-2.0-flash': 1048576,
+    'gemini/gemini-2.5-flash-preview-04-17': 1048576,
+    'gemini/gemini-2.5-flash-preview-05-20': 1048576,
     'gemini/gemini-2.5-pro-preview-03-25': 1048576,
     'gemini/gemini-2.5-pro-preview-05-06': 1048576,
     'codechat-bison': 6144,
diff --git a/tests/unittest/test_fix_json_escape_char.py b/tests/unittest/test_fix_json_escape_char.py
new file mode 100644
index 00000000..afc870a2
--- /dev/null
+++ b/tests/unittest/test_fix_json_escape_char.py
@@ -0,0 +1,21 @@
+from pr_agent.algo.utils import fix_json_escape_char
+
+
+class TestFixJsonEscapeChar:
+    def test_valid_json(self):
+        """Return unchanged when input JSON is already valid"""
+        text = '{"a": 1, "b": "ok"}'
+        expected_output = {"a": 1, "b": "ok"}
+        assert fix_json_escape_char(text) == expected_output
+
+    def test_single_control_char(self):
+        """Remove a single ASCII control-character"""
+        text = '{"msg": "hel\x01lo"}'
+        expected_output = {"msg": "hel lo"}
+        assert fix_json_escape_char(text) == expected_output
+
+    def test_multiple_control_chars(self):
+        """Remove multiple control-characters recursively"""
+        text = '{"x": "A\x02B\x03C"}'
+        expected_output = {"x": "A B C"}
+        assert fix_json_escape_char(text) == expected_output
diff --git a/tests/unittest/test_get_max_tokens.py b/tests/unittest/test_get_max_tokens.py
new file mode 100644
index 00000000..fe2f6685
--- /dev/null
+++ b/tests/unittest/test_get_max_tokens.py
@@ -0,0 +1,67 @@
+import pytest
+from pr_agent.algo.utils import get_max_tokens, MAX_TOKENS
+import pr_agent.algo.utils as utils
+
+class TestGetMaxTokens:
+
+    # Test if the file is in MAX_TOKENS
+    def test_model_max_tokens(self, monkeypatch):
+        fake_settings = type('', (), {
+            'config': type('', (), {
+                'custom_model_max_tokens': 0,
+                'max_model_tokens': 0
+            })()
+        })()
+
+        monkeypatch.setattr(utils, "get_settings", lambda: fake_settings)
+
+        model = "gpt-3.5-turbo"
+        expected = MAX_TOKENS[model]
+
+        assert get_max_tokens(model) == expected
+
+    # Test situations where the model is not registered and exists as a custom model
+    def test_model_has_custom(self, monkeypatch):
+        fake_settings = type('', (), {
+            'config': type('', (), {
+                'custom_model_max_tokens': 5000,
+                'max_model_tokens': 0  # 제한 없음
+            })()
+        })()
+
+        monkeypatch.setattr(utils, "get_settings", lambda: fake_settings)
+
+        model = "custom-model"
+        expected = 5000
+
+        assert get_max_tokens(model) == expected
+
+    def test_model_not_max_tokens_and_not_has_custom(self, monkeypatch):
+        fake_settings = type('', (), {
+            'config': type('', (), {
+                'custom_model_max_tokens': 0,
+                'max_model_tokens': 0
+            })()
+        })()
+
+        monkeypatch.setattr(utils, "get_settings", lambda: fake_settings)
+
+        model = "custom-model"
+
+        with pytest.raises(Exception):
+            get_max_tokens(model)
+
+    def test_model_max_tokens_with__limit(self, monkeypatch):
+        fake_settings = type('', (), {
+            'config': type('', (), {
+                'custom_model_max_tokens': 0,
+                'max_model_tokens': 10000
+            })()
+        })()
+
+        monkeypatch.setattr(utils, "get_settings", lambda: fake_settings)
+
+        model = "gpt-3.5-turbo"  # this model setting is 160000
+        expected = 10000
+
+        assert get_max_tokens(model) == expected
diff --git a/tests/unittest/test_language_handler.py b/tests/unittest/test_language_handler.py
index f76a15ea..8895a286 100644
--- a/tests/unittest/test_language_handler.py
+++ b/tests/unittest/test_language_handler.py
@@ -79,13 +79,14 @@ class TestSortFilesByMainLanguages:
         files = [
             type('', (object,), {'filename': 'file1.py'})(),
             type('', (object,), {'filename': 'file2.java'})(),
-            type('', (object,), {'filename': 'file3.cpp'})()
+            type('', (object,), {'filename': 'file3.cpp'})(),
+            type('', (object,), {'filename': 'file3.test'})()
         ]
         expected_output = [
             {'language': 'Python', 'files': [files[0]]},
             {'language': 'Java', 'files': [files[1]]},
             {'language': 'C++', 'files': [files[2]]},
-            {'language': 'Other', 'files': []}
+            {'language': 'Other', 'files': [files[3]]}
         ]
         assert sort_files_by_main_languages(languages, files) == expected_output