Disocvery caching is defeated by Surefire

[greenbird-chr]

When building with Kotest 4.0.1 and Maven surefire 2.2.2 Discovery.discover is called once per spec class identified by Surefire.

I noticed that my Kotest initialization time increased linearly by number of specs.

This is caused by Discovery.discover performing a full scan of the classpath for each single spec:

...
Test discovery competed in 669ms
Scan discovered 50 classes in the classpaths...
After filters there are 1 spec classes
classSelectors=[com.greenbird.metercloud.integration.flowserver.systemtest.flow.http.RestSourceValidationSpec]
...
Test discovery competed in 794ms
Scan discovered 50 classes in the classpaths...
After filters there are 1 spec classes
After discovery extensions there are 1 spec classes
classSelectors=[com.greenbird.metercloud.integration.flowserver.systemtest.flow.http.HttpReverseProxyErrorHandlingSpec]
...
Test discovery competed in 657ms
Scan discovered 50 classes in the classpaths...
After filters there are 1 spec classes
classSelectors=[com.greenbird.metercloud.integration.flowserver.systemtest.flow.http.SoapEchoSpec]
...

Discovery is caching on DiscoveryRequest but this does not help as each request is unique.

This can be fixed by also caching the result of scanUris.