Expose content type resolver api to plugins (#1752)

Expose an api which makes it easy to detect the content type of files. The api is based on the spotter api, but does not expose spotter classes.

Co-authored-by: René Pfeuffer <rene.pfeuffer@cloudogu.com>

gradle/changelog/content_type_resolver_api.yaml

@@ -0,0 +1,2 @@
+- type: Changed
+  description: Expose content type resolver api to plugins ([#1752](https://github.com/scm-manager/scm-manager/pull/1752))

scm-core/src/main/java/sonia/scm/io/ContentType.java

@@ -0,0 +1,71 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.io;
+
+import java.util.Optional;
+
+/**
+ * Detected type of content.
+ *
+ * @since 2.23.0
+ */
+public interface ContentType {
+
+  /**
+   * Returns the primary part of the content type (e.g.: text of text/plain).
+   *
+   * @return primary content type part
+   */
+  String getPrimary();
+
+  /**
+   * Returns the secondary part of the content type (e.g.: plain of text/plain).
+   *
+   * @return secondary content type part
+   */
+  String getSecondary();
+
+  /**
+   * Returns the raw presentation of the content type (e.g.: text/plain).
+   *
+   * @return raw presentation
+   */
+  String getRaw();
+
+  /**
+   * Returns {@code true} if the content type is text based.
+   *
+   * @return {@code true} for text content
+   */
+  boolean isText();
+
+  /**
+   * Returns an optional with the programming language
+   * or empty if the content is not programming language.
+   *
+   * @return programming language or empty
+   */
+  Optional<String> getLanguage();
+}

scm-core/src/main/java/sonia/scm/io/ContentTypeResolver.java

@@ -0,0 +1,52 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.io;
+
+/**
+ * ContentTypeResolver is able to detect the {@link ContentType} of files based on their path and (optinally) a few starting bytes. These files do not have to be real files on the file system, but can be hypothetical constructs ("What content type is most probable for a file named like this").
+ *
+ * @since 2.23.0
+ */
+public interface ContentTypeResolver {
+
+  /**
+   * Detects the {@link ContentType} of the given path, by only using path based strategies.
+   *
+   * @param path path of the file
+   *
+   * @return {@link ContentType} of path
+   */
+  ContentType resolve(String path);
+
+  /**
+   * Detects the {@link ContentType} of the given path, by using path and content based strategies.
+   *
+   * @param path path of the file
+   * @param contentPrefix first few bytes of the content
+   *
+   * @return {@link ContentType} of path and content prefix
+   */
+  ContentType resolve(String path, byte[] contentPrefix);
+}

scm-webapp/src/main/java/sonia/scm/api/v2/resources/ContentResource.java

@@ -24,7 +24,6 @@
 
 package sonia.scm.api.v2.resources;
 
-import com.github.sdorra.spotter.ContentType;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
 import io.swagger.v3.oas.annotations.media.Content;
@@ -33,7 +32,8 @@ import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import sonia.scm.NotFoundException;
-import sonia.scm.api.v2.ContentTypeResolver;
+import sonia.scm.io.ContentType;
+import sonia.scm.io.ContentTypeResolver;
 import sonia.scm.repository.NamespaceAndName;
 import sonia.scm.repository.api.RepositoryService;
 import sonia.scm.repository.api.RepositoryServiceFactory;
@@ -61,10 +61,12 @@ public class ContentResource {
   private static final int HEAD_BUFFER_SIZE = 1024;
 
   private final RepositoryServiceFactory serviceFactory;
+  private final ContentTypeResolver contentTypeResolver;
 
   @Inject
-  public ContentResource(RepositoryServiceFactory serviceFactory) {
+  public ContentResource(RepositoryServiceFactory serviceFactory, ContentTypeResolver contentTypeResolver) {
     this.serviceFactory = serviceFactory;
+    this.contentTypeResolver = contentTypeResolver;
   }
 
   /**
@@ -204,10 +206,10 @@ public class ContentResource {
   }
 
   private void appendContentHeader(String path, byte[] head, Response.ResponseBuilder responseBuilder) {
-    ContentType contentType = ContentTypeResolver.resolve(path, head);
+    ContentType contentType = contentTypeResolver.resolve(path, head);
     responseBuilder.header("Content-Type", contentType.getRaw());
     contentType.getLanguage().ifPresent(
-      language -> responseBuilder.header(ProgrammingLanguages.HEADER, ProgrammingLanguages.getValue(language))
+      language -> responseBuilder.header(ProgrammingLanguages.HEADER, language)
     );
   }
 

scm-webapp/src/main/java/sonia/scm/api/v2/resources/DiffResultToDiffResultDtoMapper.java

@@ -24,10 +24,9 @@
 
 package sonia.scm.api.v2.resources;
 
-import com.github.sdorra.spotter.Language;
 import com.google.inject.Inject;
 import de.otto.edison.hal.Links;
-import sonia.scm.api.v2.ContentTypeResolver;
+import sonia.scm.io.ContentTypeResolver;
 import sonia.scm.repository.Repository;
 import sonia.scm.repository.api.DiffFile;
 import sonia.scm.repository.api.DiffLine;
@@ -49,10 +48,12 @@ import static de.otto.edison.hal.Links.linkingTo;
 class DiffResultToDiffResultDtoMapper {
 
   private final ResourceLinks resourceLinks;
+  private final ContentTypeResolver contentTypeResolver;
 
   @Inject
-  DiffResultToDiffResultDtoMapper(ResourceLinks resourceLinks) {
+  DiffResultToDiffResultDtoMapper(ResourceLinks resourceLinks, ContentTypeResolver contentTypeResolver) {
     this.resourceLinks = resourceLinks;
+    this.contentTypeResolver = contentTypeResolver;
   }
 
   public DiffResultDto mapForIncoming(Repository repository, DiffResult result, String source, String target) {
@@ -154,8 +155,8 @@ class DiffResultToDiffResultDtoMapper {
     dto.setOldPath(oldPath);
     dto.setOldRevision(file.getOldRevision());
 
-    Optional<Language> language = ContentTypeResolver.resolve(path).getLanguage();
-    language.ifPresent(value -> dto.setLanguage(ProgrammingLanguages.getValue(value)));
+    Optional<String> language = contentTypeResolver.resolve(path).getLanguage();
+    language.ifPresent(dto::setLanguage);
 
     List<DiffResultDto.HunkDto> hunks = new ArrayList<>();
     for (Hunk hunk : file) {

scm-webapp/src/main/java/sonia/scm/api/v2/resources/ProgrammingLanguages.java

@@ -24,25 +24,10 @@
 
 package sonia.scm.api.v2.resources;
 
-import com.github.sdorra.spotter.Language;
-
-import java.util.Optional;
-
 final class ProgrammingLanguages {
 
   static final String HEADER = "X-Programming-Language";
 
-  private static final String DEFAULT = "text";
-
   private ProgrammingLanguages() {
   }
-
-  static String getValue(Language language) {
-    Optional<String> aceMode = language.getAceMode();
-    if (!aceMode.isPresent()) {
-      Optional<String> codemirrorMode = language.getCodemirrorMode();
-      return codemirrorMode.orElse(DEFAULT);
-    }
-    return aceMode.get();
-  }
 }

scm-webapp/src/main/java/sonia/scm/io/DefaultContentType.java

@@ -22,28 +22,45 @@
  * SOFTWARE.
  */
 
-package sonia.scm.api.v2.resources;
+package sonia.scm.io;
 
-import com.github.sdorra.spotter.Language;
-import org.junit.jupiter.api.Test;
+import java.util.Optional;
 
-import static org.assertj.core.api.Assertions.assertThat;
+public class DefaultContentType implements ContentType {
 
-class ProgrammingLanguagesTest {
+  private static final String DEFAULT_LANG_MODE = "text";
 
-  @Test
-  void shouldReturnAceModeIfPresent() {
-    assertThat(ProgrammingLanguages.getValue(Language.GO)).isEqualTo("golang");
-    assertThat(ProgrammingLanguages.getValue(Language.JAVA)).isEqualTo("java");
+  private final com.github.sdorra.spotter.ContentType contentType;
+
+  DefaultContentType(com.github.sdorra.spotter.ContentType contentType) {
+    this.contentType = contentType;
   }
 
-  @Test
-  void shouldReturnCodemirrorIfAceModeIsMissing() {
-    assertThat(ProgrammingLanguages.getValue(Language.HTML_ECR)).isEqualTo("htmlmixed");
+  @Override
+  public String getPrimary() {
+    return contentType.getPrimary();
   }
 
-  @Test
-  void shouldReturnTextIfNoModeIsPresent() {
-    assertThat(ProgrammingLanguages.getValue(Language.HXML)).isEqualTo("text");
+  @Override
+  public String getSecondary() {
+    return contentType.getSecondary();
+  }
+
+  @Override
+  public String getRaw() {
+    return contentType.getRaw();
+  }
+
+  @Override
+  public boolean isText() {
+    return contentType.isText();
+  }
+
+  @Override
+  public Optional<String> getLanguage() {
+    return contentType.getLanguage().map(language -> {
+      Optional<String> aceMode = language.getAceMode();
+      return aceMode.orElseGet(() -> language.getCodemirrorMode().orElse(DEFAULT_LANG_MODE));
+    });
   }
 }

scm-webapp/src/main/java/sonia/scm/io/DefaultContentTypeResolver.java

@@ -22,13 +22,12 @@
  * SOFTWARE.
  */
 
-package sonia.scm.api.v2;
+package sonia.scm.io;
 
-import com.github.sdorra.spotter.ContentType;
 import com.github.sdorra.spotter.ContentTypeDetector;
 import com.github.sdorra.spotter.Language;
 
-public final class ContentTypeResolver {
+public final class DefaultContentTypeResolver implements ContentTypeResolver {
 
   private static final ContentTypeDetector PATH_BASED = ContentTypeDetector.builder()
     .defaultPathBased().boost(Language.MARKDOWN)
@@ -38,14 +37,13 @@ public final class ContentTypeResolver {
     .defaultPathAndContentBased().boost(Language.MARKDOWN)
     .bestEffortMatch();
 
-  private ContentTypeResolver() {
+  @Override
+  public DefaultContentType resolve(String path) {
+    return new DefaultContentType(PATH_BASED.detect(path));
   }
 
-  public static ContentType resolve(String path) {
-    return PATH_BASED.detect(path);
-  }
-
-  public static ContentType resolve(String path, byte[] contentPrefix) {
-    return PATH_AND_CONTENT_BASED.detect(path, contentPrefix);
+  @Override
+  public DefaultContentType resolve(String path, byte[] contentPrefix) {
+    return new DefaultContentType(PATH_AND_CONTENT_BASED.detect(path, contentPrefix));
   }
 }

scm-webapp/src/main/java/sonia/scm/lifecycle/modules/ScmServletModule.java

@@ -59,6 +59,8 @@ import sonia.scm.group.GroupManagerProvider;
 import sonia.scm.group.xml.XmlGroupDAO;
 import sonia.scm.initialization.DefaultInitializationFinisher;
 import sonia.scm.initialization.InitializationFinisher;
+import sonia.scm.io.ContentTypeResolver;
+import sonia.scm.io.DefaultContentTypeResolver;
 import sonia.scm.metrics.MeterRegistryProvider;
 import sonia.scm.migration.MigrationDAO;
 import sonia.scm.net.SSLContextProvider;
@@ -290,6 +292,8 @@ class ScmServletModule extends ServletModule {
     bind(IndexQueue.class, DefaultIndexQueue.class);
     bind(SearchEngine.class, LuceneSearchEngine.class);
     bind(IndexLogStore.class, DefaultIndexLogStore.class);
+
+    bind(ContentTypeResolver.class).to(DefaultContentTypeResolver.class);
   }
 
   private <T> void bind(Class<T> clazz, Class<? extends T> defaultImplementation) {

scm-webapp/src/test/java/sonia/scm/api/v2/ContentSearchableTypeResolverTest.java

@@ -1,65 +0,0 @@
-/*
- * MIT License
- *
- * Copyright (c) 2020-present Cloudogu GmbH and Contributors
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-package sonia.scm.api.v2;
-
-import com.github.sdorra.spotter.ContentType;
-import com.github.sdorra.spotter.Language;
-import org.junit.jupiter.api.Test;
-
-import java.nio.charset.StandardCharsets;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-class ContentSearchableTypeResolverTest {
-
-  @Test
-  void shouldResolveMarkdown() {
-    String content = String.join("\n",
-      "% Markdown content",
-      "% Which does not start with markdown"
-    );
-    ContentType contentType = ContentTypeResolver.resolve("somedoc.md", content.getBytes(StandardCharsets.UTF_8));
-    assertThat(contentType.getLanguage()).contains(Language.MARKDOWN);
-  }
-
-  @Test
-  void shouldResolveMarkdownWithoutContent() {
-    ContentType contentType = ContentTypeResolver.resolve("somedoc.md");
-    assertThat(contentType.getLanguage()).contains(Language.MARKDOWN);
-  }
-
-  @Test
-  void shouldResolveMarkdownEvenWithDotsInFilename() {
-    ContentType contentType = ContentTypeResolver.resolve("somedoc.1.1.md");
-    assertThat(contentType.getLanguage()).contains(Language.MARKDOWN);
-  }
-
-  @Test
-  void shouldResolveDockerfile() {
-    ContentType contentType = ContentTypeResolver.resolve("Dockerfile");
-    assertThat(contentType.getLanguage()).contains(Language.DOCKERFILE);
-  }
-
-}

scm-webapp/src/test/java/sonia/scm/api/v2/resources/ContentResourceTest.java

@@ -29,10 +29,10 @@ import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Answers;
-import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
 import sonia.scm.NotFoundException;
+import sonia.scm.io.DefaultContentTypeResolver;
 import sonia.scm.repository.NamespaceAndName;
 import sonia.scm.repository.api.CatCommandBuilder;
 import sonia.scm.repository.api.RepositoryService;
@@ -68,13 +68,14 @@ public class ContentResourceTest {
   @Mock(answer = Answers.RETURNS_DEEP_STUBS)
   private RepositoryServiceFactory repositoryServiceFactory;
 
-  @InjectMocks
   private ContentResource contentResource;
 
   private CatCommandBuilder catCommand;
 
   @Before
   public void initService() throws Exception {
+    contentResource = new ContentResource(repositoryServiceFactory, new DefaultContentTypeResolver());
+
     NamespaceAndName existingNamespaceAndName = new NamespaceAndName(NAMESPACE, REPO_NAME);
     RepositoryService repositoryService = repositoryServiceFactory.create(existingNamespaceAndName);
     catCommand = repositoryService.getCatCommand();
@@ -169,7 +170,7 @@ public class ContentResourceTest {
   @Test
   public void shouldNotReadCompleteFileForHead() throws Exception {
     FailingAfterSomeBytesStream stream = new FailingAfterSomeBytesStream();
-    doAnswer(invocation -> stream).when(catCommand).getStream(eq("readHeadOnly"));
+    doAnswer(invocation -> stream).when(catCommand).getStream("readHeadOnly");
 
     Response response = contentResource.metadata(NAMESPACE, REPO_NAME, REV, "readHeadOnly");
     assertEquals(200, response.getStatus());
@@ -201,7 +202,7 @@ public class ContentResourceTest {
       outputStream.close();
       return null;
     }).when(catCommand).retriveContent(any(), eq(path));
-    doAnswer(invocation -> new ByteArrayInputStream(content)).when(catCommand).getStream(eq(path));
+    doAnswer(invocation -> new ByteArrayInputStream(content)).when(catCommand).getStream(path);
   }
 
   private ByteArrayOutputStream readOutputStream(Response response) throws IOException {

scm-webapp/src/test/java/sonia/scm/api/v2/resources/DiffResultToDiffResultDtoMapperTest.java

@@ -28,6 +28,7 @@ import de.otto.edison.hal.Link;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.junit.jupiter.MockitoExtension;
+import sonia.scm.io.DefaultContentTypeResolver;
 import sonia.scm.repository.Repository;
 import sonia.scm.repository.api.DiffFile;
 import sonia.scm.repository.api.DiffLine;
@@ -52,7 +53,7 @@ class DiffResultToDiffResultDtoMapperTest {
   private static final Repository REPOSITORY = new Repository("1", "git", "space", "X");
 
   ResourceLinks resourceLinks = ResourceLinksMock.createMock(create("/scm/api/v2"));
-  DiffResultToDiffResultDtoMapper mapper = new DiffResultToDiffResultDtoMapper(resourceLinks);
+  DiffResultToDiffResultDtoMapper mapper = new DiffResultToDiffResultDtoMapper(resourceLinks, new DefaultContentTypeResolver());
 
   @Test
   void shouldMapDiffResult() {

scm-webapp/src/test/java/sonia/scm/io/DefaultContentTypeResolverTest.java

@@ -0,0 +1,127 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.io;
+
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import java.nio.charset.StandardCharsets;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+class DefaultContentTypeResolverTest {
+
+  private final DefaultContentTypeResolver contentTypeResolver = new DefaultContentTypeResolver();
+
+  @Test
+  void shouldReturnPrimaryPart() {
+    ContentType contentType = contentTypeResolver.resolve("hog.pdf");
+    assertThat(contentType.getPrimary()).isEqualTo("application");
+  }
+
+  @Test
+  void shouldReturnSecondaryPart() {
+    ContentType contentType = contentTypeResolver.resolve("hog.pdf");
+    assertThat(contentType.getSecondary()).isEqualTo("pdf");
+  }
+
+  @Test
+  void shouldReturnRaw() {
+    ContentType contentType = contentTypeResolver.resolve("hog.pdf");
+    assertThat(contentType.getRaw()).isEqualTo("application/pdf");
+  }
+
+  @Nested
+  class IsTextTests {
+
+    @ParameterizedTest(name = "shouldReturnIsTextFor: {argumentsWithNames}")
+    @ValueSource(strings = {"App.java", "Dockerfile", "Playbook.yml", "README.md", "LICENSE.txt"})
+    void shouldReturnIsTextFor(String path) {
+      ContentType contentType = contentTypeResolver.resolve(path);
+      assertThat(contentType.isText()).isTrue();
+    }
+
+    @ParameterizedTest(name = "shouldReturnIsNotTextFor: {argumentsWithNames}")
+    @ValueSource(strings = {"scan.exe", "hog.pdf", "library.so", "awesome.dll", "something.dylib"})
+    void shouldReturnIsNotTextFor(String path) {
+      ContentType contentType = contentTypeResolver.resolve(path);
+      assertThat(contentType.isText()).isFalse();
+    }
+  }
+
+  @Nested
+  class LanguageTests {
+
+    @Test
+    void shouldResolveMarkdown() {
+      String content = String.join("\n",
+        "% Markdown content",
+        "% Which does not start with markdown"
+      );
+      ContentType contentType = contentTypeResolver.resolve("somedoc.md", content.getBytes(StandardCharsets.UTF_8));
+      Assertions.assertThat(contentType.getLanguage()).contains("markdown");
+    }
+
+    @Test
+    void shouldResolveMarkdownWithoutContent() {
+      ContentType contentType = contentTypeResolver.resolve("somedoc.md");
+      Assertions.assertThat(contentType.getLanguage()).contains("markdown");
+    }
+
+    @Test
+    void shouldResolveMarkdownEvenWithDotsInFilename() {
+      ContentType contentType = contentTypeResolver.resolve("somedoc.1.1.md");
+      Assertions.assertThat(contentType.getLanguage()).contains("markdown");
+    }
+
+    @Test
+    void shouldResolveDockerfile() {
+      ContentType contentType = contentTypeResolver.resolve("Dockerfile");
+      Assertions.assertThat(contentType.getLanguage()).contains("dockerfile");
+    }
+
+
+    @Test
+    void shouldReturnAceModeIfPresent() {
+      assertThat(contentTypeResolver.resolve("app.go").getLanguage()).contains("golang"); // codemirror is just go
+      assertThat(contentTypeResolver.resolve("App.java").getLanguage()).contains("java"); // codemirror is clike
+    }
+
+    @Test
+    void shouldReturnCodemirrorIfAceModeIsMissing() {
+      assertThat(contentTypeResolver.resolve("index.ecr").getLanguage()).contains("htmlmixed");
+    }
+
+    @Test
+    void shouldReturnTextIfNoModeIsPresent() {
+      assertThat(contentTypeResolver.resolve("index.hxml").getLanguage()).contains("text");
+    }
+
+  }
+
+}