Add Testcontainers integration tests for SAML newslist flow

[Copilot]

Summary

Adds end-to-end integration tests using Testcontainers and HtmlUnit that exercise the full SAML 2.0 SSO login flow of the newslist application.

A real SimpleSAMLphp IdP is started in Docker (jamedjo/test-saml-idp, the same image used in the demo docker-compose.yml) alongside the Spring Boot application. HtmlUnit drives a headless browser through the complete SSO flow.

Changes

build.gradle

• Replace net.sourceforge.htmlunit:htmlunit (legacy, unmaintained) with org.htmlunit:htmlunit managed by the Spring Boot 4 BOM (version 4.17.0).
• Add org.testcontainers:testcontainers and org.testcontainers:testcontainers-junit-jupiter (version 2.0.5, managed by the Spring Boot 4 BOM).

src/test/resources/news/

Two minimal CSV news files are added:

File	Key	Content
News Item 1.csv	1	Your first test news item
News Item 2.csv	1	Your second test news item

Both entries use key 1, which matches the uid attribute of user1 in the test IdP. user2 (uid 2) has no entries and sees an empty list.

src/test/java/…/NewsListIntegrationTest.java

Five test cases covering the main flows:

Test	Description
unauthenticatedUserIsRedirectedToSamlLogin	Unauthenticated GET / is redirected to the SimpleSAMLphp login page
authenticatedUserWithMatchingNewsSeesTheirItems	user1 logs in and sees both news items
authenticatedUserWithoutMatchingNewsSeesEmptyList	user2 logs in and sees no news items
emailAddressFromSamlAttributeIsDisplayed	The email SAML attribute is shown on the index page
newsItemTitleIsDisplayedCorrectly	The news item title is derived from the CSV filename

How the chicken-and-egg port problem is solved: A free port is pre-allocated via ServerSocket(0) in a static initialiser before the Testcontainers @Container is created. The IdP is configured with the SP ACS URL using that port, and @DynamicPropertySource injects server.port so Spring Boot binds to the same port.

.github/workflows/build.yml

Adds a gradle test step so the new tests run in CI.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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