test: add test for ambiguous StorageFormat.ZARR behavior

Signed-off-by: Caleb Hulbert <cmhulbert@gmail.com>

Author: cmhulbert

src/test/java/org/janelia/saalfeldlab/n5/universe/N5FactoryTests.java

@@ -11,8 +11,10 @@
 import org.janelia.saalfeldlab.n5.hdf5.N5HDF5Writer;
 import org.janelia.saalfeldlab.n5.zarr.ZarrKeyValueReader;
 import org.janelia.saalfeldlab.n5.zarr.ZarrKeyValueWriter;
+import org.janelia.saalfeldlab.n5.zarr.v3.ZarrV3KeyValueReader;
 import org.janelia.saalfeldlab.n5.zarr.v3.ZarrV3KeyValueWriter;
 import org.junit.Test;
+import org.junit.runners.Parameterized;
 
 import java.io.File;
 import java.io.IOException;
@@ -280,6 +282,42 @@ public void testDefaultForAmbiguousWriters() throws IOException {
 		}
 	}
 
+	@Test
+	public void testAmbiguousZarrFormat() throws IOException {
+
+		final N5Factory factory = new N5Factory();
+		File tmpDir = Files.createTempDirectory("factory-test-").toFile();
+
+		/* by default, should be zarr 3 with no other information */
+		URI doesntExistsIsZarr3 = tmpDir.toPath().resolve("doesnt_exists_is_zarr3").toUri();
+		N5Writer n5 = factory.openWriter(StorageFormat.ZARR, doesntExistsIsZarr3);
+		assertEquals(ZarrV3KeyValueWriter.class, n5.getClass());
+
+		/* If a zarr2 container exists, it should correctly return zarr2 */
+		URI explicitZarr2 = tmpDir.toPath().resolve("explicit_zarr2").toUri();
+		N5Writer explicitZarr2n5 = factory.openWriter(StorageFormat.ZARR2, explicitZarr2);
+		assertEquals(ZarrKeyValueWriter.class, explicitZarr2n5.getClass());
+
+		N5Reader guessZarr2Reader = factory.openReader(StorageFormat.ZARR, explicitZarr2);
+		assertEquals(ZarrKeyValueReader.class, guessZarr2Reader.getClass());
+
+		N5Reader guessZarr2Writer = factory.openWriter(StorageFormat.ZARR, explicitZarr2);
+		assertEquals(ZarrKeyValueWriter.class, guessZarr2Writer.getClass());
+
+		/* If zarr container is valid Zarr2 and Zarr3, should return zarr3 preferentially */
+		URI bothZarrs = tmpDir.toPath().resolve("both_zarr2_zarr3").toUri();
+		N5Writer bothZarr2 = factory.openWriter(StorageFormat.ZARR2, bothZarrs);
+		assertEquals(ZarrKeyValueReader.class, factory.openReader(StorageFormat.ZARR, bothZarrs).getClass());
+		assertEquals(ZarrKeyValueWriter.class, factory.openWriter(StorageFormat.ZARR, bothZarrs).getClass());
+
+		N5Writer bothZarr3 = factory.openWriter(StorageFormat.ZARR3, bothZarrs);
+		assertEquals(ZarrV3KeyValueReader.class, factory.openReader(StorageFormat.ZARR, bothZarrs).getClass());
+		assertEquals(ZarrV3KeyValueWriter.class, factory.openWriter(StorageFormat.ZARR, bothZarrs).getClass());
+
+		assertEquals(ZarrKeyValueReader.class, factory.openReader(StorageFormat.ZARR2, bothZarrs).getClass());
+		assertEquals(ZarrKeyValueWriter.class, factory.openWriter(StorageFormat.ZARR2, bothZarrs).getClass());
+	}
+
 	@Test
 	public void testForExistingWriters() throws IOException {
 
@@ -292,7 +330,7 @@ public void testForExistingWriters() throws IOException {
 			final Object[][] testData = new Object[][] {
 					{"h5WithWeirdExtension.zarr", StorageFormat.HDF5, N5HDF5Writer.class},
 					{"zarr2WithWeirdExtension.n5", StorageFormat.ZARR2, ZarrKeyValueWriter.class},
-					{"zarr3WithWeirdExtension.jpg", StorageFormat.ZARR, ZarrV3KeyValueWriter.class},
+					{"zarr3WithWeirdExtension.jpg", StorageFormat.ZARR3, ZarrV3KeyValueWriter.class},
 					{"n5WithWeirdExtension.h5", StorageFormat.N5, N5KeyValueWriter.class},
 			};