Fix import of invalid flexible areas

[vpaturet]

Summary

When importing a NeTEx flex stop containing multiple areas, the graph builder crashes if one of the areas is invalid while the others are valid.

An uncaught error occurred inside OTP: java.lang.IllegalArgumentException: geometries must not contain null elements java.lang.RuntimeException: java.lang.IllegalArgumentException: geometries must not contain null elements
at org.opentripplanner.netex.NetexModule.buildGraph(NetexModule.java:123)
at org.opentripplanner.graph_builder.GraphBuilder.run(GraphBuilder.java:211)
at org.opentripplanner.standalone.OTPMain.startOTPServer(OTPMain.java:142)
at org.opentripplanner.standalone.OTPMain.main(OTPMain.java:55) Caused by: java.lang.IllegalArgumentException: geometries must not contain null elements
at org.locationtech.jts.geom.GeometryCollection.<init>(GeometryCollection.java:54)
at org.opentripplanner.transit.model.site.GroupStopBuilder.withEncompassingAreaGeometries(GroupStopBuilder.java:59)
at org.opentripplanner.netex.mapping.FlexStopsMapper.map(FlexStopsMapper.java:106)
at org.opentripplanner.netex.mapping.NetexMapper.mapFlexibleStopPlaces(NetexMapper.java:381)
at org.opentripplanner.netex.mapping.NetexMapper.mapNetexToOtp(NetexMapper.java:193)
at org.opentripplanner.netex.NetexBundle.loadFilesThenMapToTimetableRepository(NetexBundle.java:179)
at org.opentripplanner.netex.NetexBundle.lambda$loadFileEntries$1(NetexBundle.java:134)
at org.opentripplanner.netex.NetexBundle.scopeInputData(NetexBundle.java:155)
at org.opentripplanner.netex.NetexBundle.loadFileEntries(NetexBundle.java:132)
at org.opentripplanner.netex.NetexBundle.loadBundle(NetexBundle.java:106)
at org.opentripplanner.netex.NetexModule.buildGraph(NetexModule.java:75)

This PR fixes this corner-case.

Issue

No

Unit tests

Added unit test.
There was a latent bug in the unit tests where GroupStops were incorrectly cast to AreaStop. The bug was silent since the cast applied only to null references. This is fixed.

Documentation

No

Changelog

skip

[leonardehrenfried]

Data producers will always find new ways to produce invalid data. :)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.22%. Comparing base (b7ed036) to head (13ef984).
⚠️ Report is 275 commits behind head on dev-2.x.

Additional details and impacted files

@@              Coverage Diff              @@
##             dev-2.x    #7043      +/-   ##
=============================================
+ Coverage      72.11%   72.22%   +0.11%     
- Complexity     20058    20164     +106     
=============================================
  Files           2177     2188      +11     
  Lines          80926    81188     +262     
  Branches        8135     8142       +7     
=============================================
+ Hits           58359    58641     +282     
+ Misses         19697    19670      -27     
- Partials        2870     2877       +7     

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[t2gran]

This looks fine, just a small update to doc

[leonardehrenfried]

It appears that @t2gran has taken over my review so I let him also give the approval.