diff --git a/contributing/samples/gepa/experiment.py b/contributing/samples/gepa/experiment.py
index f3751206a8..2710c3894c 100644
--- a/contributing/samples/gepa/experiment.py
+++ b/contributing/samples/gepa/experiment.py
@@ -43,7 +43,6 @@
 from tau_bench.types import EnvRunResult
 from tau_bench.types import RunConfig
 import tau_bench_agent as tau_bench_agent_lib
-
 import utils
 
 
diff --git a/contributing/samples/gepa/run_experiment.py b/contributing/samples/gepa/run_experiment.py
index d857da9635..e31db15788 100644
--- a/contributing/samples/gepa/run_experiment.py
+++ b/contributing/samples/gepa/run_experiment.py
@@ -25,7 +25,6 @@
 from absl import flags
 import experiment
 from google.genai import types
-
 import utils
 
 _OUTPUT_DIR = flags.DEFINE_string(
diff --git a/src/google/adk/examples/example_util.py b/src/google/adk/examples/example_util.py
index 5f95b4953e..6c6f213d73 100644
--- a/src/google/adk/examples/example_util.py
+++ b/src/google/adk/examples/example_util.py
@@ -46,7 +46,6 @@
 _FUNCTION_RESPONSE_SUFFIX = "\n```\n"
 
 
-# TODO(yaojie): Add unit tests for this function.
 def convert_examples_to_text(
     examples: list[Example], model: Optional[str]
 ) -> str:
diff --git a/tests/unittests/examples/__init__.py b/tests/unittests/examples/__init__.py
new file mode 100644
index 0000000000..58d482ea38
--- /dev/null
+++ b/tests/unittests/examples/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2026 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.
diff --git a/tests/unittests/examples/test_example_util.py b/tests/unittests/examples/test_example_util.py
new file mode 100644
index 0000000000..7950552bd8
--- /dev/null
+++ b/tests/unittests/examples/test_example_util.py
@@ -0,0 +1,458 @@
+# Copyright 2026 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.
+
+"""Tests for example_util."""
+
+from google.adk.examples import base_example_provider
+from google.adk.examples import example
+from google.adk.examples import example_util
+from google.genai import types
+import pytest
+
+BASIC_INPUT = types.Content(role="user", parts=[types.Part(text="test_input")])
+
+BASIC_OUTPUT = [
+    types.Content(role="model", parts=[types.Part(text="test_output")])
+]
+
+BASIC_EXAMPLE = example.Example(input=BASIC_INPUT, output=BASIC_OUTPUT)
+
+
+class MockExampleProvider(base_example_provider.BaseExampleProvider):
+  """Mocks an ExampleProvider object.
+
+  This class provides mock implementation of the get_examples() function,
+  allowing the user to test functions that rely on an ExampleProvider
+  without creating a real ExampleProvider class and check that the correct
+  inputs are being passed to it.
+  """
+
+  def __init__(
+      self, test_examples: list[example.Example], test_query: str
+  ) -> None:
+    """Initializes a MockExampleProvider.
+
+    Args:
+        test_examples: The list of examples to be returned on a successful query.
+        test_query: The query necessary to return a correct output.
+    """
+    self.test_examples = test_examples
+    self.test_query = test_query
+
+  def get_examples(self, query: str) -> list[example.Example]:
+    """Mocks querying the ExampleProvider for examples.
+    Verifies the query is correct, and returns an empty list if not.
+
+    Args:
+        query: The query to check examples for.
+    """
+    if query == self.test_query:
+      return self.test_examples
+    else:
+      return []
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_text_only_example_conversion(model):
+  """Tests converting a text-only Example object to a string for use in a system instruction."""
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}"
+      f"{example_util._EXAMPLE_START.format(1)}"
+      f"{example_util._USER_PREFIX}test_input\n"
+      f"{example_util._MODEL_PREFIX}test_output\n"
+      f"{example_util._EXAMPLE_END}"
+      f"{example_util._EXAMPLES_END}"
+  )
+
+  assert (
+      example_util.convert_examples_to_text(
+          examples=[BASIC_EXAMPLE], model=model
+      )
+      == expected_output
+  )
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_multi_part_text_example_conversion(model):
+  """Tests converting an Example object with multiple text Parts to a string for use in a system instruction."""
+  output_content = [
+      types.Content(
+          role="model",
+          parts=[
+              types.Part(text="test_output_1"),
+              types.Part(text="test_output_2"),
+              types.Part(text="test_output_3"),
+          ],
+      )
+  ]
+  test_example = example.Example(input=BASIC_INPUT, output=output_content)
+
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}"
+      f"{example_util._EXAMPLE_START.format(1)}"
+      f"{example_util._USER_PREFIX}test_input\n"
+      f"{example_util._MODEL_PREFIX}test_output_1\ntest_output_2\ntest_output_3\n"
+      f"{example_util._EXAMPLE_END}"
+      f"{example_util._EXAMPLES_END}"
+  )
+
+  assert (
+      example_util.convert_examples_to_text(
+          examples=[test_example], model=model
+      )
+      == expected_output
+  )
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_example_conversion_prefix_insertion(model):
+  """Tests if user and model prefixes are properly alternated when converting an Example object to text for use in a system instruction."""
+  output_content = [
+      types.Content(role="model", parts=[types.Part(text="test_output_1")]),
+      types.Content(role="user", parts=[types.Part(text="test_output_2")]),
+      types.Content(role="model", parts=[types.Part(text="test_output_3")]),
+  ]
+  test_example = example.Example(input=BASIC_INPUT, output=output_content)
+
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}"
+      f"{example_util._EXAMPLE_START.format(1)}"
+      f"{example_util._USER_PREFIX}test_input\n"
+      f"{example_util._MODEL_PREFIX}test_output_1\n"
+      f"{example_util._USER_PREFIX}test_output_2\n"
+      f"{example_util._MODEL_PREFIX}test_output_3\n"
+      f"{example_util._EXAMPLE_END}"
+      f"{example_util._EXAMPLES_END}"
+  )
+
+  assert (
+      example_util.convert_examples_to_text(
+          examples=[test_example], model=model
+      )
+      == expected_output
+  )
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_example_conversion_output_clumping(model):
+  """Tests whether user and model inputs are properly clumped when converting an Example object to text for use in a system instruction."""
+  output_content = [
+      types.Content(role="model", parts=[types.Part(text="test_output_1")]),
+      types.Content(role="model", parts=[types.Part(text="test_output_2")]),
+      types.Content(role="user", parts=[types.Part(text="test_output_3")]),
+      types.Content(role="user", parts=[types.Part(text="test_output_4")]),
+  ]
+  test_example = example.Example(input=BASIC_INPUT, output=output_content)
+
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}"
+      f"{example_util._EXAMPLE_START.format(1)}"
+      f"{example_util._USER_PREFIX}test_input\n"
+      f"{example_util._MODEL_PREFIX}test_output_1\ntest_output_2\n"
+      f"{example_util._USER_PREFIX}test_output_3\ntest_output_4\n"
+      f"{example_util._EXAMPLE_END}"
+      f"{example_util._EXAMPLES_END}"
+  )
+
+  assert (
+      example_util.convert_examples_to_text(
+          examples=[test_example], model=model
+      )
+      == expected_output
+  )
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_empty_examples_list_conversion(model):
+  """Tests Example conversion to text if the examples list is empty."""
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}{example_util._EXAMPLES_END}"
+  )
+
+  assert (
+      example_util.convert_examples_to_text(examples=[], model=model)
+      == expected_output
+  )
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_example_conversion_with_function_call(model):
+  """Tests converting an Example object containing a function call to a string for use in a system instruction."""
+  test_function_call = types.FunctionCall(
+      name="test_function",
+      args={"test_string_argument": "test_value", "test_int_argument": 1},
+  )
+  output_content = [
+      types.Content(
+          role="model", parts=[types.Part(function_call=test_function_call)]
+      )
+  ]
+  test_example = example.Example(input=BASIC_INPUT, output=output_content)
+
+  gemini2 = model is None or "gemini-2" in model
+  prefix = (
+      example_util._FUNCTION_PREFIX
+      if gemini2
+      else example_util._FUNCTION_CALL_PREFIX
+  )
+
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}"
+      f"{example_util._EXAMPLE_START.format(1)}"
+      f"{example_util._USER_PREFIX}test_input\n"
+      f"{example_util._MODEL_PREFIX}{prefix}"
+      "test_function(test_string_argument='test_value', test_int_argument=1)"
+      f"{example_util._FUNCTION_CALL_SUFFIX}"
+      f"{example_util._EXAMPLE_END}"
+      f"{example_util._EXAMPLES_END}"
+  )
+
+  assert (
+      example_util.convert_examples_to_text(
+          examples=[test_example], model=model
+      )
+      == expected_output
+  )
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_example_conversion_with_function_response(model):
+  """Tests converting an Example object containing a function response to a string for use in a system instruction."""
+  test_function_response = types.FunctionResponse(
+      name="test_function",
+      response={"test_string_argument": "test_value", "test_int_argument": 1},
+  )
+  output_content = [
+      types.Content(
+          role="model",
+          parts=[types.Part(function_response=test_function_response)],
+      )
+  ]
+  test_example = example.Example(input=BASIC_INPUT, output=output_content)
+
+  gemini2 = model is None or "gemini-2" in model
+  prefix = (
+      example_util._FUNCTION_PREFIX
+      if gemini2
+      else example_util._FUNCTION_RESPONSE_PREFIX
+  )
+
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}"
+      f"{example_util._EXAMPLE_START.format(1)}"
+      f"{example_util._USER_PREFIX}test_input\n"
+      f"{example_util._MODEL_PREFIX}{prefix}"
+      f"{test_function_response.__dict__}"
+      f"{example_util._FUNCTION_RESPONSE_SUFFIX}"
+      f"{example_util._EXAMPLE_END}"
+      f"{example_util._EXAMPLES_END}"
+  )
+
+  assert (
+      example_util.convert_examples_to_text(
+          examples=[test_example], model=model
+      )
+      == expected_output
+  )
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_example_conversion_with_function_call_response(model):
+  """Tests converting an Example object containing a function call and response to a string for use in a system instruction."""
+  test_function_call = types.FunctionCall(
+      name="test_function",
+      args={"test_string_argument": "test_value", "test_int_argument": 1},
+  )
+  test_function_response = types.FunctionResponse(
+      name="test_function",
+      response={"test_string_argument": "test_value", "test_int_argument": 1},
+  )
+  output_content = [
+      types.Content(
+          role="model",
+          parts=[
+              types.Part(function_call=test_function_call),
+              types.Part(function_response=test_function_response),
+          ],
+      )
+  ]
+  test_example = example.Example(input=BASIC_INPUT, output=output_content)
+
+  gemini2 = model is None or "gemini-2" in model
+  response_prefix = (
+      example_util._FUNCTION_PREFIX
+      if gemini2
+      else example_util._FUNCTION_RESPONSE_PREFIX
+  )
+  call_prefix = (
+      example_util._FUNCTION_PREFIX
+      if gemini2
+      else example_util._FUNCTION_CALL_PREFIX
+  )
+
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}"
+      f"{example_util._EXAMPLE_START.format(1)}"
+      f"{example_util._USER_PREFIX}test_input\n"
+      f"{example_util._MODEL_PREFIX}{call_prefix}"
+      "test_function(test_string_argument='test_value', test_int_argument=1)"
+      f"{example_util._FUNCTION_CALL_SUFFIX}"
+      f"{response_prefix}"
+      f"{test_function_response.__dict__}"
+      f"{example_util._FUNCTION_RESPONSE_SUFFIX}"
+      f"{example_util._EXAMPLE_END}"
+      f"{example_util._EXAMPLES_END}"
+  )
+
+  assert (
+      example_util.convert_examples_to_text(
+          examples=[test_example], model=model
+      )
+      == expected_output
+  )
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_example_conversion_with_text_and_function_call_response(model):
+  """Tests converting an Example object containing text, a function call, and a function response to a string for use in a system instruction."""
+  test_function_call = types.FunctionCall(
+      name="test_function",
+      args={"test_string_argument": "test_value", "test_int_argument": 1},
+  )
+  test_function_response = types.FunctionResponse(
+      name="test_function",
+      response={"test_string_argument": "test_value", "test_int_argument": 1},
+  )
+  output_content = [
+      types.Content(
+          role="model",
+          parts=[
+              types.Part(text="test_output"),
+              types.Part(function_call=test_function_call),
+              types.Part(function_response=test_function_response),
+          ],
+      )
+  ]
+  test_example = example.Example(input=BASIC_INPUT, output=output_content)
+
+  gemini2 = model is None or "gemini-2" in model
+  response_prefix = (
+      example_util._FUNCTION_PREFIX
+      if gemini2
+      else example_util._FUNCTION_RESPONSE_PREFIX
+  )
+  call_prefix = (
+      example_util._FUNCTION_PREFIX
+      if gemini2
+      else example_util._FUNCTION_CALL_PREFIX
+  )
+
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}"
+      f"{example_util._EXAMPLE_START.format(1)}"
+      f"{example_util._USER_PREFIX}test_input\n"
+      f"{example_util._MODEL_PREFIX}test_output\n"
+      f"{call_prefix}"
+      "test_function(test_string_argument='test_value', test_int_argument=1)"
+      f"{example_util._FUNCTION_CALL_SUFFIX}"
+      f"{response_prefix}"
+      f"{test_function_response.__dict__}"
+      f"{example_util._FUNCTION_RESPONSE_SUFFIX}"
+      f"{example_util._EXAMPLE_END}"
+      f"{example_util._EXAMPLES_END}"
+  )
+
+  assert (
+      example_util.convert_examples_to_text(
+          examples=[test_example], model=model
+      )
+      == expected_output
+  )
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_building_si_from_list(model):
+  """Tests building System Information from a list of examples."""
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}"
+      f"{example_util._EXAMPLE_START.format(1)}"
+      f"{example_util._USER_PREFIX}test_input\n"
+      f"{example_util._MODEL_PREFIX}test_output\n"
+      f"{example_util._EXAMPLE_END}"
+      f"{example_util._EXAMPLES_END}"
+  )
+
+  assert (
+      example_util.build_example_si(
+          examples=[BASIC_EXAMPLE], query="", model=model
+      )
+      == expected_output
+  )
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["gemini-2.5-flash", "llama3_vertex_agent", None],
+)
+def test_building_si_from_base_example_provider(model):
+  """Tests building System Information from an example provider."""
+  expected_output = (
+      f"{example_util._EXAMPLES_INTRO}"
+      f"{example_util._EXAMPLE_START.format(1)}"
+      f"{example_util._USER_PREFIX}test_input\n"
+      f"{example_util._MODEL_PREFIX}test_output\n"
+      f"{example_util._EXAMPLE_END}"
+      f"{example_util._EXAMPLES_END}"
+  )
+
+  example_provider = MockExampleProvider(
+      test_examples=[BASIC_EXAMPLE], test_query="test_query"
+  )
+
+  assert (
+      example_util.build_example_si(
+          examples=example_provider, query="test_query", model=model
+      )
+      == expected_output
+  )