test: data (entity) graphs with loops

Author: Pfeil

src/test/java/edu/kit/datamanager/ro_crate/crate/ReadAndWriteTest.java

@@ -53,6 +53,6 @@ void testReadCrateWithHasPartHierarchy() {
     RoCrateReader reader = new RoCrateReader(new FolderReader());
     RoCrate crate = reader.readCrate(ReadAndWriteTest.class.getResource("/crates/hasPartHierarchy").getPath());
     assertEquals(1, crate.getAllContextualEntities().size());
-    assertEquals(4, crate.getAllDataEntities().size());
+    assertEquals(6, crate.getAllDataEntities().size());
   }
 }

src/test/resources/crates/hasPartHierarchy/README.md

@@ -0,0 +1,12 @@
+# hasPart/isPartOf Structure in this crate
+
+This documents the hierarchy in this json file for the hasPart property.
+"isPartOf" occurences are handled the inverse way (as if it was a hasPart property the other way around).
+
+- ./
+  - sub-a.file
+  - sub-b.file
+    - sub-b-sub-a.file
+      - looper.file --> sub-b.file  
+    - sub-b-sub-b.file (isPartOf)
+    - looper-isPartOf.file --> sub-b.file

src/test/resources/crates/hasPartHierarchy/ro-crate-metadata.json

@@ -42,12 +42,24 @@
         },
         {
             "@id": "sub-b-sub-a.file",
-            "@type": "File"
+            "@type": "File",
+            "hasPart": {"@id": "looper.file"}
         },
         {
             "@id": "sub-b-sub-b.file",
             "@type": "File",
             "isPartOf": { "@id": "sub-b.file" }
+        },
+        {
+            "@id": "looper.file",
+            "@type": "File",
+            "hasPart": {"@id": "sub-b.file"}
+        },
+        {
+            "@id": "looper-isPartOf.file",
+            "@type": "File",
+            "hasPart": {"@id": "sub-b.file"},
+            "isPartOf": {"@id": "sub-b.file"}
         }
     ]
 }