diff --git a/tests/unittests/code_executors/__init__.py b/tests/unittests/code_executors/__init__.py
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+++ b/tests/unittests/code_executors/__init__.py
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+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
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diff --git a/tests/unittests/code_executors/test_code_executor_context.py b/tests/unittests/code_executors/test_code_executor_context.py
new file mode 100644
index 0000000..1802fb2
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+++ b/tests/unittests/code_executors/test_code_executor_context.py
@@ -0,0 +1,275 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from google.adk.code_executors.code_execution_utils import File
+from google.adk.code_executors.code_executor_context import CodeExecutorContext
+from google.adk.sessions.state import State
+import pytest
+
+
+@pytest.fixture
+def empty_state() -> State:
+  """Fixture for an empty session state."""
+  return State({}, {})
+
+
+@pytest.fixture
+def context_with_data() -> CodeExecutorContext:
+  """Fixture for a CodeExecutorContext with some pre-populated data."""
+  state_data = {
+      "_code_execution_context": {
+          "execution_session_id": "session123",
+          "processed_input_files": ["file1.csv", "file2.txt"],
+      },
+      "_code_executor_input_files": [
+          {"name": "input1.txt", "content": "YQ==", "mime_type": "text/plain"}
+      ],
+      "_code_executor_error_counts": {"invocationA": 2},
+  }
+  state = State(state_data, {})
+  return CodeExecutorContext(state)
+
+
+def test_init_empty_state(empty_state: State):
+  """Test initialization with an empty state."""
+  ctx = CodeExecutorContext(empty_state)
+  assert ctx._context == {}
+  assert ctx._session_state is empty_state
+
+
+def test_get_state_delta_empty(empty_state: State):
+  """Test get_state_delta when context is empty."""
+  ctx = CodeExecutorContext(empty_state)
+  delta = ctx.get_state_delta()
+  assert delta == {"_code_execution_context": {}}
+
+
+def test_get_state_delta_with_data(context_with_data: CodeExecutorContext):
+  """Test get_state_delta with existing context data."""
+  delta = context_with_data.get_state_delta()
+  expected_context = {
+      "execution_session_id": "session123",
+      "processed_input_files": ["file1.csv", "file2.txt"],
+  }
+  assert delta == {"_code_execution_context": expected_context}
+
+
+def test_get_execution_id_exists(context_with_data: CodeExecutorContext):
+  """Test getting an existing execution ID."""
+  assert context_with_data.get_execution_id() == "session123"
+
+
+def test_get_execution_id_not_exists(empty_state: State):
+  """Test getting execution ID when it doesn't exist."""
+  ctx = CodeExecutorContext(empty_state)
+  assert ctx.get_execution_id() is None
+
+
+def test_set_execution_id(empty_state: State):
+  """Test setting an execution ID."""
+  ctx = CodeExecutorContext(empty_state)
+  ctx.set_execution_id("new_session_id")
+  assert ctx._context["execution_session_id"] == "new_session_id"
+  assert ctx.get_execution_id() == "new_session_id"
+
+
+def test_get_processed_file_names_exists(
+    context_with_data: CodeExecutorContext,
+):
+  """Test getting existing processed file names."""
+  assert context_with_data.get_processed_file_names() == [
+      "file1.csv",
+      "file2.txt",
+  ]
+
+
+def test_get_processed_file_names_not_exists(empty_state: State):
+  """Test getting processed file names when none exist."""
+  ctx = CodeExecutorContext(empty_state)
+  assert ctx.get_processed_file_names() == []
+
+
+def test_add_processed_file_names_new(empty_state: State):
+  """Test adding processed file names to an empty context."""
+  ctx = CodeExecutorContext(empty_state)
+  ctx.add_processed_file_names(["new_file.py"])
+  assert ctx._context["processed_input_files"] == ["new_file.py"]
+
+
+def test_add_processed_file_names_append(
+    context_with_data: CodeExecutorContext,
+):
+  """Test appending to existing processed file names."""
+  context_with_data.add_processed_file_names(["another_file.md"])
+  assert context_with_data.get_processed_file_names() == [
+      "file1.csv",
+      "file2.txt",
+      "another_file.md",
+  ]
+
+
+def test_get_input_files_exists(context_with_data: CodeExecutorContext):
+  """Test getting existing input files."""
+  files = context_with_data.get_input_files()
+  assert len(files) == 1
+  assert files[0].name == "input1.txt"
+  assert files[0].content == "YQ=="
+  assert files[0].mime_type == "text/plain"
+
+
+def test_get_input_files_not_exists(empty_state: State):
+  """Test getting input files when none exist."""
+  ctx = CodeExecutorContext(empty_state)
+  assert ctx.get_input_files() == []
+
+
+def test_add_input_files_new(empty_state: State):
+  """Test adding input files to an empty session state."""
+  ctx = CodeExecutorContext(empty_state)
+  new_files = [File(name="new.dat", content="Yg==", mime_type="application/octet-stream")]
+  ctx.add_input_files(new_files)
+  assert empty_state["_code_executor_input_files"] == [
+      {"name": "new.dat", "content": "Yg==", "mime_type": "application/octet-stream"}
+  ]
+
+
+def test_add_input_files_append(context_with_data: CodeExecutorContext):
+  """Test appending to existing input files."""
+  new_file = File(name="input2.log", content="Yw==", mime_type="text/x-log")
+  context_with_data.add_input_files([new_file])
+  expected_files_data = [
+      {"name": "input1.txt", "content": "YQ==", "mime_type": "text/plain"},
+      {"name": "input2.log", "content": "Yw==", "mime_type": "text/x-log"},
+  ]
+  assert (
+      context_with_data._session_state["_code_executor_input_files"]
+      == expected_files_data
+  )
+
+
+def test_clear_input_files(context_with_data: CodeExecutorContext):
+  """Test clearing input files and processed file names."""
+  context_with_data.clear_input_files()
+  assert context_with_data._session_state["_code_executor_input_files"] == []
+  assert context_with_data._context["processed_input_files"] == []
+
+
+def test_clear_input_files_when_not_exist(empty_state: State):
+  """Test clearing input files when they don't exist initially."""
+  ctx = CodeExecutorContext(empty_state)
+  ctx.clear_input_files()  # Should not raise error
+  assert "_code_executor_input_files" not in empty_state  # Or assert it's empty
+  assert "_code_execution_context" not in empty_state or not empty_state[
+      "_code_execution_context"
+  ].get("processed_input_files")
+
+
+def test_get_error_count_exists(context_with_data: CodeExecutorContext):
+  """Test getting an existing error count."""
+  assert context_with_data.get_error_count("invocationA") == 2
+
+
+def test_get_error_count_invocation_not_exists(
+    context_with_data: CodeExecutorContext,
+):
+  """Test getting error count for an unknown invocation ID."""
+  assert context_with_data.get_error_count("invocationB") == 0
+
+
+def test_get_error_count_no_error_key(empty_state: State):
+  """Test getting error count when the error key itself doesn't exist."""
+  ctx = CodeExecutorContext(empty_state)
+  assert ctx.get_error_count("any_invocation") == 0
+
+
+def test_increment_error_count_new_invocation(empty_state: State):
+  """Test incrementing error count for a new invocation ID."""
+  ctx = CodeExecutorContext(empty_state)
+  ctx.increment_error_count("invocationNew")
+  assert empty_state["_code_executor_error_counts"]["invocationNew"] == 1
+
+
+def test_increment_error_count_existing_invocation(
+    context_with_data: CodeExecutorContext,
+):
+  """Test incrementing error count for an existing invocation ID."""
+  context_with_data.increment_error_count("invocationA")
+  assert (
+      context_with_data._session_state["_code_executor_error_counts"][
+          "invocationA"
+      ]
+      == 3
+  )
+
+
+def test_reset_error_count_exists(context_with_data: CodeExecutorContext):
+  """Test resetting an existing error count."""
+  context_with_data.reset_error_count("invocationA")
+  assert "invocationA" not in (
+      context_with_data._session_state["_code_executor_error_counts"]
+  )
+
+
+def test_reset_error_count_not_exists(context_with_data: CodeExecutorContext):
+  """Test resetting an error count that doesn't exist."""
+  context_with_data.reset_error_count("invocationB")  # Should not raise
+  assert "invocationB" not in (
+      context_with_data._session_state["_code_executor_error_counts"]
+  )
+
+
+def test_reset_error_count_no_error_key(empty_state: State):
+  """Test resetting when the error key itself doesn't exist."""
+  ctx = CodeExecutorContext(empty_state)
+  ctx.reset_error_count("any_invocation")  # Should not raise
+  assert "_code_executor_error_counts" not in empty_state
+
+
+def test_update_code_execution_result_new_invocation(empty_state: State):
+  """Test updating code execution result for a new invocation."""
+  ctx = CodeExecutorContext(empty_state)
+  ctx.update_code_execution_result(
+      "inv1", "print('hi')", "hi", ""
+  )
+  results = empty_state["_code_execution_results"]["inv1"]
+  assert len(results) == 1
+  assert results[0]["code"] == "print('hi')"
+  assert results[0]["result_stdout"] == "hi"
+  assert results[0]["result_stderr"] == ""
+  assert "timestamp" in results[0]
+
+
+def test_update_code_execution_result_append(
+    context_with_data: CodeExecutorContext,
+):
+  """Test appending to existing code execution results for an invocation."""
+  # First, let's add an initial result for a new invocation to the existing state
+  context_with_data._session_state["_code_execution_results"] = {
+      "invocationX": [{
+          "code": "old_code",
+          "result_stdout": "old_out",
+          "result_stderr": "old_err",
+          "timestamp": 123,
+      }]
+  }
+  context_with_data.update_code_execution_result(
+      "invocationX", "new_code", "new_out", "new_err"
+  )
+  results = context_with_data._session_state["_code_execution_results"][
+      "invocationX"
+  ]
+  assert len(results) == 2
+  assert results[1]["code"] == "new_code"
+  assert results[1]["result_stdout"] == "new_out"
+  assert results[1]["result_stderr"] == "new_err"
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