feat: Added junit test for application controllers

Refs: DEV-12343

src/test/java/ch/sbb/polarion/extension/pdf_exporter/rest/PdfExporterRestApplicationTest.java

@@ -0,0 +1,71 @@
+package ch.sbb.polarion.extension.pdf_exporter.rest;
+
+import ch.sbb.polarion.extension.generic.util.ManifestUtils;
+import com.google.inject.AbstractModule;
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import com.polarion.alm.tracker.ITestManagementService;
+import com.polarion.platform.core.IPlatform;
+import com.polarion.platform.core.PlatformContext;
+import com.polarion.platform.guice.internal.GuicePlatform;
+import com.polarion.platform.security.ISecurityService;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.MockedStatic;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.lang.reflect.Field;
+import java.util.jar.Attributes;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+class PdfExporterRestApplicationTest {
+
+    @Mock
+    private ITestManagementService testManagementService;
+
+    @BeforeEach
+    void setUp() throws Exception {
+        Injector injector = Guice.createInjector(new PdfExporterRestApplicationTest.TestModule(testManagementService));
+        Field field = GuicePlatform.class.getDeclaredField("globalInjector");
+        field.setAccessible(true);
+        field.set(null, injector);
+    }
+
+
+    @Test
+    void shouldInstantiateControllers() {
+
+        try (MockedStatic<PlatformContext> platformContext = mockStatic(PlatformContext.class)) {
+            IPlatform platform = mock(IPlatform.class);
+            platformContext.when(PlatformContext::getPlatform).thenReturn(platform);
+            ISecurityService securityService = mock(ISecurityService.class);
+            when(platform.lookupService(ISecurityService.class)).thenReturn(securityService);
+            try (MockedStatic<ManifestUtils> manifestUtils = mockStatic(ManifestUtils.class)) {
+                Attributes attributes = new Attributes();
+                attributes.putValue("Extension-Context", "test");
+                manifestUtils.when(ManifestUtils::getManifestAttributes).thenReturn(attributes);
+                PdfExporterRestApplication application = new PdfExporterRestApplication();
+                assertThat(application.getExtensionControllerSingletons()).hasSize(10);
+            }
+        }
+    }
+
+    public static class TestModule extends AbstractModule {
+        private final ITestManagementService testManagementService;
+
+        public TestModule(ITestManagementService testManagementService) {
+            this.testManagementService = testManagementService;
+        }
+
+        @Override
+        protected void configure() {
+            bind(ITestManagementService.class).toInstance(testManagementService);
+        }
+    }
+
+}