implement simplified PluginManager API

scm-webapp/src/test/java/sonia/scm/plugin/PluginCenterTest.java

@@ -0,0 +1,73 @@
+package sonia.scm.plugin;
+
+import com.google.common.collect.ImmutableSet;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Answers;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import sonia.scm.SCMContextProvider;
+import sonia.scm.cache.CacheManager;
+import sonia.scm.cache.MapCacheManager;
+import sonia.scm.config.ScmConfiguration;
+import sonia.scm.net.ahc.AdvancedHttpClient;
+import sonia.scm.util.SystemUtil;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+class PluginCenterTest {
+
+  private static final String PLUGIN_URL_BASE = "https://plugins.hitchhiker.com/";
+  private static final String PLUGIN_URL = PLUGIN_URL_BASE + "{version}";
+
+  @Mock
+  private PluginCenterLoader loader;
+
+  @Mock
+  private SCMContextProvider contextProvider;
+
+  private ScmConfiguration configuration;
+
+  private CacheManager cacheManager;
+
+  private PluginCenter pluginCenter;
+
+  @BeforeEach
+  void setUpPluginCenter() {
+    when(contextProvider.getVersion()).thenReturn("2.0.0");
+
+    cacheManager = new MapCacheManager();
+
+    configuration = new ScmConfiguration();
+    configuration.setPluginUrl(PLUGIN_URL);
+
+    pluginCenter = new PluginCenter(contextProvider, cacheManager, configuration, loader);
+  }
+
+  @Test
+  void shouldFetchPlugins() {
+    Set<AvailablePlugin> plugins = new HashSet<>();
+    when(loader.load(PLUGIN_URL_BASE + "2.0.0")).thenReturn(plugins);
+
+    assertThat(pluginCenter.getAvailable()).isSameAs(plugins);
+  }
+
+  @Test
+  void shouldCache() {
+    Set<AvailablePlugin> first = new HashSet<>();
+    when(loader.load(anyString())).thenReturn(first, new HashSet<>());
+
+    assertThat(pluginCenter.getAvailable()).isSameAs(first);
+    assertThat(pluginCenter.getAvailable()).isSameAs(first);
+  }
+
+}