Add unit tests for email sender

app/core/tests/test_email_sender.py

@@ -0,0 +1,301 @@
+import logging
+import pytest
+from pathlib import Path
+from unittest.mock import MagicMock
+
+from app.core.email_sender import EmailSender, LocalEmailSender, SmtpEmailSender, get_email_sender
+from app.core.settings import SettingsDep
+from app.fixtures.email_factory import EmailFactory
+
+
+@pytest.fixture
+def email_templates_fixture(tmp_path: Path) -> tuple[Path, Path]:
+    html_template = tmp_path / "test.mjml"
+    text_template = tmp_path / "test.txt"
+
+    _ = html_template.write_text("""
+    <mjml>
+        <mj-body>
+            <mj-text>Hello {{ name}}</mj-text>
+        </mj-body>
+    </mjml>
+    """)
+
+    _ = text_template.write_text("Hello {{ name }}")
+
+    return html_template, text_template
+
+
+# Test get_email_sender dependency injection for EmailSender
+# ----------------------------------------------------------------------------------------------------------------------
+
+
+def test_get_email_sender_returns_local_sender_when_email_sender_type_is_local(settings_fixture: SettingsDep):
+    settings_fixture.email_sender_type = "local"
+    sender = get_email_sender(settings_fixture)
+    assert isinstance(sender, LocalEmailSender)
+    assert sender.settings == settings_fixture
+
+
+def test_get_email_sender_returns_smtp_sender_when_email_sender_type_is_smtp(settings_fixture: SettingsDep):
+    settings_fixture.email_sender_type = "smtp"
+    sender = get_email_sender(settings_fixture)
+    assert isinstance(sender, SmtpEmailSender)
+    assert sender.settings == settings_fixture
+
+
+def test_get_email_sender_raises_not_implemented_error_for_invalid_email_sender_types(settings_fixture: SettingsDep):
+    settings_fixture.email_sender_type = "invalid"  # pyright: ignore[reportAttributeAccessIssue]
+    with pytest.raises(NotImplementedError, match="Email sender type 'invalid' is not implemented."):
+        _ = get_email_sender(settings_fixture)
+
+
+@pytest.mark.asyncio
+async def test_base_email_sender_raises_not_implemented(
+    settings_fixture: SettingsDep, email_templates_fixture: tuple[Path, Path]
+):
+    html_template, text_template = email_templates_fixture
+    email = EmailFactory.build(body_html_template=html_template, body_text_template=text_template)
+    mock_self = MagicMock()
+
+    with pytest.raises(NotImplementedError):
+        _ = await EmailSender.send_email(mock_self, email)  # pyright: ignore[reportAbstractUsage]
+
+
+def test_render_logs_error_and_returns_raw_content_on_mjml_failure(
+    settings_fixture: SettingsDep,
+    email_templates_fixture: tuple[Path, Path],
+    caplog: pytest.LogCaptureFixture,
+    monkeypatch: pytest.MonkeyPatch,
+):
+    sender = LocalEmailSender(settings_fixture)
+    html_template, _ = email_templates_fixture
+    mock_mjml = MagicMock(side_effect=Exception("Simulated MJML Failure"))
+    monkeypatch.setattr("app.core.email_sender.mjml2html", mock_mjml)
+    result = sender.render("html", html_template, {"name": "ErrorTest"})
+
+    assert "Failed to compile MJML to HTML" in caplog.text
+    assert "Hello ErrorTest" in result
+
+
+# Test LocalEmailSender send_email which logs emails
+# ----------------------------------------------------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_send_email_logs_details_and_returns_placeholder(
+    settings_fixture: SettingsDep,
+    email_templates_fixture: tuple[Path, Path],
+    caplog: pytest.LogCaptureFixture,
+):
+    caplog.set_level(logging.DEBUG)
+    settings_fixture.email_sender_type = "local"
+    sender = LocalEmailSender(settings_fixture)
+    html_template, text_template = email_templates_fixture
+    email = EmailFactory.build(subject="Test", body_html_template=html_template, body_text_template=text_template)
+    message_id = await sender.send_email(email)
+
+    assert message_id == "local-message-id-placeholder"
+    assert "Simulated sending email to" in caplog.text
+    assert "recipient@testemail.com" in caplog.text
+    assert "Test" in caplog.text
+
+
+@pytest.mark.asyncio
+async def test_send_email_with_multiple_receivers_logs_all_recipients(
+    settings_fixture: SettingsDep, caplog: pytest.LogCaptureFixture, email_templates_fixture: tuple[Path, Path]
+):
+    settings_fixture.email_sender_type = "local"
+    sender = LocalEmailSender(settings_fixture)
+    html_template, text_template = email_templates_fixture
+    email = EmailFactory.build(
+        receivers=["recipient1@testemail.com", "recipient2@testemail.com"],
+        body_html_template=html_template,
+        body_text_template=text_template,
+    )
+    message_id = await sender.send_email(email)
+
+    assert message_id == "local-message-id-placeholder"
+    assert "recipient1@testemail.com" in caplog.text
+    assert "recipient2@testemail.com" in caplog.text
+
+
+# Test LocalEmailSender render which renders an email template of the given type
+# ----------------------------------------------------------------------------------------------------------------------
+
+
+def test_render_text_template_with_data(settings_fixture: SettingsDep, email_templates_fixture: tuple[Path, Path]):
+    sender = LocalEmailSender(settings_fixture)
+    _, text_template = email_templates_fixture
+    result = sender.render("text", text_template, {"name": "John"})
+
+    assert "Hello John" in result
+
+
+def test_render_text_template_empty_data(settings_fixture: SettingsDep, email_templates_fixture: tuple[Path, Path]):
+    sender = LocalEmailSender(settings_fixture)
+    _, text_template = email_templates_fixture
+    result = sender.render("text", text_template, {})
+
+    assert "Hello" in result
+
+
+def test_render_html_template_with_data(settings_fixture: SettingsDep, email_templates_fixture: tuple[Path, Path]):
+    sender = LocalEmailSender(settings_fixture)
+    html_template, _ = email_templates_fixture
+    result = sender.render("html", html_template, {"name": "Alice"})
+
+    assert "Hello Alice" in result
+
+
+def test_render_with_none_template_data(settings_fixture: SettingsDep, email_templates_fixture: tuple[Path, Path]):
+    sender = LocalEmailSender(settings_fixture)
+    _, text_template = email_templates_fixture
+    result = sender.render("text", text_template, None)
+
+    assert isinstance(result, str)
+    assert "Hello" in result
+
+
+def test_render_preserves_template_variables_without_data(settings_fixture: SettingsDep, tmp_path: Path):
+    sender = LocalEmailSender(settings_fixture)
+    text_template = tmp_path / "test_vars.txt"
+    _ = text_template.write_text("Hello {{ name }}, your email is {{ email }}")
+    result = sender.render("text", text_template, None)
+
+    assert "Hello" in result
+
+
+def test_render_complex_template_data(settings_fixture: SettingsDep, tmp_path: Path):
+    sender = LocalEmailSender(settings_fixture)
+    text_template = tmp_path / "complex.txt"
+    _ = text_template.write_text("User: {{ user.name }}, Email: {{ user.email }}")
+    result = sender.render("text", text_template, {"user": {"name": "Bob", "email": "bob@example.com"}})
+
+    assert "User: Bob" in result
+    assert "bob@example.com" in result
+
+
+def test_render_methods_are_available(settings_fixture: SettingsDep, email_templates_fixture: tuple[Path, Path]):
+    sender = SmtpEmailSender(settings_fixture)
+    _, text_template = email_templates_fixture
+    result = sender.render("text", text_template, {"name": "Test"})
+
+    assert "Hello Test" in result
+
+
+# Test SmtpEmailSender
+# ----------------------------------------------------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_send_email_raises_exception_when_smtp_connection_fails(
+    settings_fixture: SettingsDep, monkeypatch: pytest.MonkeyPatch, email_templates_fixture: tuple[Path, Path]
+):
+    monkeypatch.setattr(settings_fixture, "email_sender_type", "smtp")
+    monkeypatch.setattr(settings_fixture, "email_smtp_host", "invalid-host-xyz")
+    monkeypatch.setattr(settings_fixture, "email_smtp_port", 9595)
+    monkeypatch.setattr(settings_fixture, "email_smtp_use_ssl", False)
+    monkeypatch.setattr(settings_fixture, "email_smtp_use_tls", False)
+    mock_smtp_cls = MagicMock(side_effect=Exception("Simulated Connection Error"))
+    monkeypatch.setattr("app.core.email_sender.smtplib.SMTP", mock_smtp_cls)
+    sender = SmtpEmailSender(settings_fixture)
+    html_template, text_template = email_templates_fixture
+    email = EmailFactory.build(body_html_template=html_template, body_text_template=text_template)
+    with pytest.raises(Exception, match="Simulated Connection Error"):
+        _ = await sender.send_email(email)
+
+
+@pytest.mark.asyncio
+async def test_send_email_logs_network_error_during_sending(
+    settings_fixture: SettingsDep,
+    caplog: pytest.LogCaptureFixture,
+    monkeypatch: pytest.MonkeyPatch,
+    email_templates_fixture: tuple[Path, Path],
+):
+    caplog.set_level(logging.ERROR)
+    monkeypatch.setattr(settings_fixture, "email_sender_type", "smtp")
+    mock_smtp_cls = MagicMock(side_effect=Exception("Major Network Fail"))
+    monkeypatch.setattr("app.core.email_sender.smtplib.SMTP", mock_smtp_cls)
+    sender = SmtpEmailSender(settings_fixture)
+    html_template, text_template = email_templates_fixture
+    email = EmailFactory.build(body_html_template=html_template, body_text_template=text_template)
+    with pytest.raises(Exception):
+        _ = await sender.send_email(email)
+
+    assert "Failed to send email via SMTP" in caplog.text
+    assert "Major Network Fail" in caplog.text
+
+
+@pytest.mark.asyncio
+async def test_send_email_with_attachments_gets_added_to_the_MIME_multipart(
+    settings_fixture: SettingsDep, monkeypatch: pytest.MonkeyPatch, email_templates_fixture: tuple[Path, Path]
+):
+    monkeypatch.setattr(settings_fixture, "email_sender_type", "smtp")
+    monkeypatch.setattr(settings_fixture, "email_smtp_use_ssl", False)
+    monkeypatch.setattr(settings_fixture, "email_smtp_use_tls", False)
+    mock_smtp_cls = MagicMock()
+    mock_instance = mock_smtp_cls.return_value
+    monkeypatch.setattr("app.core.email_sender.smtplib.SMTP", mock_smtp_cls)
+    sender = SmtpEmailSender(settings_fixture)
+    html_template, text_template = email_templates_fixture
+    email = EmailFactory.build(body_html_template=html_template, body_text_template=text_template)
+    email.attachments = {"report.pdf": b"%PDF-1.4 content..."}
+    _ = await sender.send_email(email)
+
+    mock_instance.send_message.assert_called_once()
+    sent_message = mock_instance.send_message.call_args[0][0]
+    attachment_found = False
+    for part in sent_message.walk():
+        if part.get_filename() == "report.pdf":
+            attachment_found = True
+            assert part["Content-Disposition"] == 'attachment; filename="report.pdf"'
+    assert attachment_found, "Attachment part was not found in the MIME message"
+
+
+@pytest.mark.asyncio
+async def test_send_email_follows_correct_flow_for_tls_connection_with_login(
+    settings_fixture: SettingsDep, monkeypatch: pytest.MonkeyPatch, email_templates_fixture: tuple[Path, Path]
+):
+    monkeypatch.setattr(settings_fixture, "email_sender_type", "smtp")
+    monkeypatch.setattr(settings_fixture, "email_smtp_host", "smtp.example.com")
+    monkeypatch.setattr(settings_fixture, "email_smtp_port", 587)
+    monkeypatch.setattr(settings_fixture, "email_smtp_use_ssl", False)
+    monkeypatch.setattr(settings_fixture, "email_smtp_use_tls", True)
+    monkeypatch.setattr(settings_fixture, "email_smtp_username", "testuser")
+    monkeypatch.setattr(settings_fixture, "email_smtp_password", "testpass")
+    mock_smtp_cls = MagicMock()
+    mock_instance = mock_smtp_cls.return_value
+    monkeypatch.setattr("app.core.email_sender.smtplib.SMTP", mock_smtp_cls)
+    sender = SmtpEmailSender(settings_fixture)
+    html_template, text_template = email_templates_fixture
+    email = EmailFactory.build(body_html_template=html_template, body_text_template=text_template)
+    _ = await sender.send_email(email)
+
+    mock_smtp_cls.assert_called_with("smtp.example.com", 587)
+    mock_instance.starttls.assert_called_once()
+    mock_instance.login.assert_called_once_with("testuser", "testpass")
+    mock_instance.send_message.assert_called_once()
+    mock_instance.quit.assert_called_once()
+
+
+@pytest.mark.asyncio
+async def test_send_email_follows_correct_flow_for_ssl(
+    settings_fixture: SettingsDep, monkeypatch: pytest.MonkeyPatch, email_templates_fixture: tuple[Path, Path]
+):
+    monkeypatch.setattr(settings_fixture, "email_sender_type", "smtp")
+    monkeypatch.setattr(settings_fixture, "email_smtp_host", "smtp.secure.com")
+    monkeypatch.setattr(settings_fixture, "email_smtp_port", 465)
+    monkeypatch.setattr(settings_fixture, "email_smtp_use_ssl", True)
+    mock_smtp_cls = MagicMock()
+    mock_instance = mock_smtp_cls.return_value
+    monkeypatch.setattr("app.core.email_sender.smtplib.SMTP_SSL", mock_smtp_cls)
+    sender = SmtpEmailSender(settings_fixture)
+    html_template, text_template = email_templates_fixture
+    email = EmailFactory.build(body_html_template=html_template, body_text_template=text_template)
+    _ = await sender.send_email(email)
+    mock_instance = mock_smtp_cls.return_value
+
+    mock_smtp_cls.assert_called_with("smtp.secure.com", 465)
+    mock_instance.send_message.assert_called_once()
+    mock_instance.quit.assert_called_once()