implemented plugin installation

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

@@ -0,0 +1,90 @@
+package sonia.scm.plugin;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junitpioneer.jupiter.TempDirectory;
+import org.mockito.Answers;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import sonia.scm.SCMContextProvider;
+import sonia.scm.net.ahc.AdvancedHttpClient;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Path;
+import java.util.Collections;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.in;
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.when;
+
+@ExtendWith({MockitoExtension.class, TempDirectory.class})
+class PluginInstallerTest {
+
+  @Mock
+  private SCMContextProvider context;
+
+  @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+  private AdvancedHttpClient client;
+
+  @InjectMocks
+  private PluginInstaller installer;
+
+  private Path directory;
+
+  @BeforeEach
+  void setUpContext(@TempDirectory.TempDir Path directory) {
+    this.directory = directory;
+    when(context.getBaseDirectory()).thenReturn(directory.toFile());
+  }
+
+  @Test
+  void shouldDownloadPlugin() throws IOException {
+    mockContent("42");
+
+    installer.install(createGitPlugin());
+
+    assertThat(directory.resolve("plugins").resolve("scm-git-plugin.smp")).hasContent("42");
+  }
+
+  private void mockContent(String content) throws IOException {
+    when(client.get("https://download.hitchhiker.com").request().contentAsStream())
+      .thenReturn(new ByteArrayInputStream(content.getBytes(StandardCharsets.UTF_8)));
+  }
+
+  private AvailablePlugin createGitPlugin() {
+    return createPlugin(
+      "scm-git-plugin",
+      "https://download.hitchhiker.com",
+      "73475cb40a568e8da8a045ced110137e159f890ac4da883b6b17dc651b3a8049" // 42
+    );
+  }
+
+  @Test
+  void shouldThrowPluginDownloadException() throws IOException {
+    when(client.get("https://download.hitchhiker.com").request()).thenThrow(new IOException("failed to download"));
+
+    assertThrows(PluginDownloadException.class, () -> installer.install(createGitPlugin()));
+  }
+
+  @Test
+  void shouldThrowPluginChecksumMismatchException() throws IOException {
+    mockContent("21");
+
+    assertThrows(PluginChecksumMismatchException.class, () -> installer.install(createGitPlugin()));
+  }
+
+
+  private AvailablePlugin createPlugin(String name, String url, String checksum) {
+    PluginInformation information = new PluginInformation();
+    information.setName(name);
+    AvailablePluginDescriptor descriptor = new AvailablePluginDescriptor(
+      information, null, Collections.emptySet(), url, checksum
+    );
+    return new AvailablePlugin(descriptor);
+  }
+}