diff --git a/tests/scrapers/conftest.py b/tests/scrapers/conftest.py
new file mode 100644
index 0000000..3248ec2
--- /dev/null
+++ b/tests/scrapers/conftest.py
@@ -0,0 +1,41 @@
+import pytest
+
+
+@pytest.fixture
+def mock_codeforces_html():
+    return """
+    <div class="input">
+        <pre>
+            <div class="test-example-line-1">3</div>
+            <div class="test-example-line-1">1 2 3</div>
+        </pre>
+    </div>
+    <div class="output">
+        <pre>
+            <div class="test-example-line-1">6</div>
+        </pre>
+    </div>
+    """
+
+
+@pytest.fixture
+def mock_atcoder_html():
+    return """
+    <h3>Sample Input 1</h3>
+    <pre>3
+1 2 3</pre>
+    <h3>Sample Output 1</h3>
+    <pre>6</pre>
+    """
+
+
+@pytest.fixture
+def mock_cses_html():
+    return """
+    <h1>Example</h1>
+    <p>Input:</p>
+    <pre>3
+1 2 3</pre>
+    <p>Output:</p>
+    <pre>6</pre>
+    """
diff --git a/tests/scrapers/test_atcoder.py b/tests/scrapers/test_atcoder.py
new file mode 100644
index 0000000..5086894
--- /dev/null
+++ b/tests/scrapers/test_atcoder.py
@@ -0,0 +1,50 @@
+from unittest.mock import Mock
+from scrapers.atcoder import scrape, scrape_contest_problems
+
+
+def test_scrape_success(mocker, mock_atcoder_html):
+    mock_response = Mock()
+    mock_response.text = mock_atcoder_html
+
+    mocker.patch("scrapers.atcoder.requests.get", return_value=mock_response)
+
+    result = scrape("https://atcoder.jp/contests/abc350/tasks/abc350_a")
+
+    assert len(result) == 1
+    assert result[0][0] == "3\n1 2 3"
+    assert result[0][1] == "6"
+
+
+def test_scrape_contest_problems(mocker):
+    mock_response = Mock()
+    mock_response.text = """
+    <table class="table">
+        <tr><th>Task</th><th>Name</th></tr>
+        <tr>
+            <td></td>
+            <td><a href="/contests/abc350/tasks/abc350_a">A - Water Tank</a></td>
+        </tr>
+        <tr>
+            <td></td>
+            <td><a href="/contests/abc350/tasks/abc350_b">B - Dentist Aoki</a></td>
+        </tr>
+    </table>
+    """
+
+    mocker.patch("scrapers.atcoder.requests.get", return_value=mock_response)
+
+    result = scrape_contest_problems("abc350")
+
+    assert len(result) == 2
+    assert result[0] == {"id": "a", "name": "A - Water Tank"}
+    assert result[1] == {"id": "b", "name": "B - Dentist Aoki"}
+
+
+def test_scrape_network_error(mocker):
+    mocker.patch(
+        "scrapers.atcoder.requests.get", side_effect=Exception("Network error")
+    )
+
+    result = scrape("https://atcoder.jp/contests/abc350/tasks/abc350_a")
+
+    assert result == []
diff --git a/tests/scrapers/test_codeforces.py b/tests/scrapers/test_codeforces.py
new file mode 100644
index 0000000..67277ea
--- /dev/null
+++ b/tests/scrapers/test_codeforces.py
@@ -0,0 +1,53 @@
+from unittest.mock import Mock
+from scrapers.codeforces import scrape, scrape_contest_problems
+from scrapers.models import Problem
+
+
+def test_scrape_success(mocker, mock_codeforces_html):
+    mock_scraper = Mock()
+    mock_response = Mock()
+    mock_response.text = mock_codeforces_html
+    mock_scraper.get.return_value = mock_response
+
+    mocker.patch(
+        "scrapers.codeforces.cloudscraper.create_scraper", return_value=mock_scraper
+    )
+
+    result = scrape("https://codeforces.com/contest/1900/problem/A")
+
+    assert len(result) == 1
+    assert result[0].input == "1\n3\n1 2 3"
+    assert result[0].expected == "6"
+
+
+def test_scrape_contest_problems(mocker):
+    mock_scraper = Mock()
+    mock_response = Mock()
+    mock_response.text = """
+    <a href="/contest/1900/problem/A">A. Problem A</a>
+    <a href="/contest/1900/problem/B">B. Problem B</a>
+    """
+    mock_scraper.get.return_value = mock_response
+
+    mocker.patch(
+        "scrapers.codeforces.cloudscraper.create_scraper", return_value=mock_scraper
+    )
+
+    result = scrape_contest_problems("1900")
+
+    assert len(result) == 2
+    assert result[0] == Problem(id="a", name="A. Problem A")
+    assert result[1] == Problem(id="b", name="B. Problem B")
+
+
+def test_scrape_network_error(mocker):
+    mock_scraper = Mock()
+    mock_scraper.get.side_effect = Exception("Network error")
+
+    mocker.patch(
+        "scrapers.codeforces.cloudscraper.create_scraper", return_value=mock_scraper
+    )
+
+    result = scrape("https://codeforces.com/contest/1900/problem/A")
+
+    assert result == []
diff --git a/tests/scrapers/test_cses.py b/tests/scrapers/test_cses.py
new file mode 100644
index 0000000..1dd0096
--- /dev/null
+++ b/tests/scrapers/test_cses.py
@@ -0,0 +1,46 @@
+from unittest.mock import Mock
+from scrapers.cses import scrape, scrape_all_problems
+
+
+def test_scrape_success(mocker, mock_cses_html):
+    mock_response = Mock()
+    mock_response.text = mock_cses_html
+
+    mocker.patch("scrapers.cses.requests.get", return_value=mock_response)
+
+    result = scrape("https://cses.fi/problemset/task/1068")
+
+    assert len(result) == 1
+    assert result[0][0] == "3\n1 2 3"
+    assert result[0][1] == "6"
+
+
+def test_scrape_all_problems(mocker):
+    mock_response = Mock()
+    mock_response.text = """
+    <h1>Introductory Problems</h1>
+    <a href="/problemset/task/1068">Weird Algorithm</a>
+    <a href="/problemset/task/1083">Missing Number</a>
+    <h1>Sorting and Searching</h1>
+    <a href="/problemset/task/1084">Apartments</a>
+    """
+
+    mocker.patch("scrapers.cses.requests.get", return_value=mock_response)
+
+    result = scrape_all_problems()
+
+    assert "Introductory Problems" in result
+    assert "Sorting and Searching" in result
+    assert len(result["Introductory Problems"]) == 2
+    assert result["Introductory Problems"][0] == {
+        "id": "1068",
+        "name": "Weird Algorithm",
+    }
+
+
+def test_scrape_network_error(mocker):
+    mocker.patch("scrapers.cses.requests.get", side_effect=Exception("Network error"))
+
+    result = scrape("https://cses.fi/problemset/task/1068")
+
+    assert result == []