CgmesImporter, allow importing with wrong dataextension when the main…

…file doesn't exist

This happens when filenames have the 2 following properties:
- the filename contains a dot:
- the filename does not contain the dataextension
For example this filename triggers the bug:  "microgrid.v2.complete.zip"
but these work:
   "microgrid_v2_complete.zip" (because empty dataextension)
or "microgrid.v2.complete.xml.zip" (because ".xml" dataextension)

The problem is that the main extension is derived as ".v2.complete" but the
cgmes importer only accepts an empty dataextension or ".xml" (it checks the
dataextension to avoid importing as cgmes from a datasource that was meant by
the user to be used as another format). But for now no other importer works
without a main file, so when the mainfile doesn't exist so we shouldn't block
the import just like when the dataextension is not specified

NOTE: this happens because we want to allow archive filenames to be very
flexible (with or without the dataextension, and for cgmes even with a totally
different basename as what is inside).

NOTE: if we ever have another importer that works like the cgmes importer,
this means we will not be able to handle the following case:
archive/network_EQ.xml
archive/network_TP.xml # cgmes files
archive/network_foo.other
archive/network_bar.other # some new importer format
and be able to import from a single directory containing both networks by specifying
the dataextension. But this should be a rare case, and moving the data to separate
directories or using separate basenames works around the problem.

cgmes/cgmes-model/src/main/java/com/powsybl/cgmes/model/CgmesOnDataSource.java

@@ -35,7 +35,7 @@ public ReadOnlyDataSource dataSource() {
     }
 
     private boolean checkIfMainFileNotWithCgmesData(boolean isCim14) throws IOException {
-        if (dataSource.getDataExtension() == null || dataSource.getDataExtension().isEmpty()) {
+        if (dataSource.getDataExtension() == null || dataSource.getDataExtension().isEmpty() || !dataSource.exists(null, dataSource.getDataExtension())) {
             return false;
         } else if (EXTENSION.equals(dataSource.getDataExtension()) && dataSource.exists(null, EXTENSION)) {
             try (InputStream is = dataSource.newInputStream(null, EXTENSION)) {

cgmes/cgmes-model/src/test/java/com/powsybl/cgmes/model/CgmesOnDataSourceTest.java

@@ -28,6 +28,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * @author Jon Harper {@literal <jon.harper at rte-france.com>}
@@ -71,13 +72,24 @@ void testFileDoesNotExist() throws IOException {
                     byte[] data = "Test String".getBytes();
                     out.write(data, 0, data.length);
                     out.closeEntry();
+                    e = new ZipEntry("foo.xml");
+                    out.putNextEntry(e);
+                    data = getClass().getResourceAsStream("/empty_cim16_EQ.xml").readAllBytes();
+                    out.write(data, 0, data.length);
+                    out.closeEntry();
                 } catch (IOException ex) {
                     throw new RuntimeException(ex);
                 }
             }
             ReadOnlyDataSource dataSource = new ZipArchiveDataSource(testDir, "foo.iidm.zip", "test", "xml", null);
             CgmesOnDataSource cgmesOnDataSource = new CgmesOnDataSource(dataSource);
-            assertFalse(cgmesOnDataSource.exists());
+            assertTrue(cgmesOnDataSource.exists());
+            ReadOnlyDataSource dataSource2 = new ZipArchiveDataSource(testDir, "foo.iidm.zip", "test", "iidm", null);
+            CgmesOnDataSource cgmesOnDataSource2 = new CgmesOnDataSource(dataSource2);
+            assertTrue(cgmesOnDataSource2.exists());
+            ReadOnlyDataSource dataSource3 = new ZipArchiveDataSource(testDir, "foo.iidm.zip", "foo", "bar", null);
+            CgmesOnDataSource cgmesOnDataSource3 = new CgmesOnDataSource(dataSource3);
+            assertFalse(cgmesOnDataSource3.exists());
         }
     }
 }