feat(#1660): Add RepositoryStatistics class and corresponding test

src/main/java/com/jcabi/github/RepositoryStatistics.java

@@ -0,0 +1,53 @@
+package com.jcabi.github;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Map;
+import java.util.stream.Collectors;
+import javax.json.JsonObject;
+import javax.json.JsonValue;
+import org.cactoos.map.MapEntry;
+import org.cactoos.map.MapOf;
+
+public class RepositoryStatistics {
+    private final Repo repo;
+
+    public RepositoryStatistics(final Repo repo) {
+        this.repo = repo;
+    }
+
+    Map<String, Object> toMap() throws IOException {
+        final JsonObject json = repo.json();
+        return new MapOf<>(
+            Arrays.stream(KEY.values()).map(key -> key.toEntry(json)).collect(Collectors.toList())
+        );
+    }
+
+    private enum KEY {
+        LANGUAGE("language"),
+        FORKS_COUNT("forks_count"),
+        STARGAZERS_COUNT("stargazers_count"),
+        WATCHERS_COUNT("watchers_count"),
+        SIZE("size"),
+        OPEN_ISSUES_COUNT("open_issues_count"),
+        CREATED_AT("created_at"),
+        UPDATED_AT("updated_at");
+
+        private final String key;
+
+        KEY(final String key) {
+            this.key = key;
+        }
+
+        private MapEntry<String, Object> toEntry(final JsonObject object) {
+            final String k = this.getKey();
+            final JsonValue value = object.get(k);
+            return new MapEntry<>(k, value.toString());
+        }
+
+        public String getKey() {
+            return key;
+        }
+    }
+}
+

src/test/java/com/jcabi/github/RepositoryStatisticsTest.java

@@ -0,0 +1,32 @@
+package com.jcabi.github;
+
+import java.io.IOException;
+import java.util.Map;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+/**
+ * Test case for {@link RepositoryStatistics}.
+ *
+ */
+public class RepositoryStatisticsTest {
+
+    @Test
+    public void gathersBasicStatisticsFromRepo() throws IOException {
+        MatcherAssert.assertThat(
+            "We expect to have basic statistics from repo",
+            new RepositoryStatistics(null).toMap(),
+            Matchers.allOf(
+                Matchers.hasKey("language"),
+                Matchers.hasKey("forks_count"),
+                Matchers.hasKey("stargazers_count"),
+                Matchers.hasKey("watchers_count"),
+                Matchers.hasKey("size"),
+                Matchers.hasKey("open_issues_count"),
+                Matchers.hasKey("created_at"),
+                Matchers.hasKey("updated_at")
+            )
+        );
+    }
+}