Multiple BCL test failures when MONO_BUILD_FROM_SOURCE=1 is used

[spouliot]

Steps to Reproduce

1. create a xamarin-macios branch
2. switch external/mono to a custom mono branch
3. add MONO_BUILD_FROM_SOURCE=1 to Make.config
4. commit / push
5. check bot results

Expected Behavior

A lot of BCL unit tests fails building because it expects binaries to be available for unit tests.

That's good, unless your working on something not mergeable right away. In that case you get a lot of false positive. It would be better to detect this (env variable) and put the tests status to Ignore

Actual Behavior

http://xamarin-storage/jenkins/xamarin-macios/xi-interpreter/e862008477898385a03c201bf8df783f7fee3f70/15/jenkins-results/tests/index.html

Environment

master

Example Project (If Possible)

branch xi-interpreter shows this

[spouliot]

c.c. @mandel-macaque for comments / alternative ideas

[rolfbjarne]

Ideally the test assemblies would be built when we build mono (from source), and put in the expected location (by mono).

[spouliot]

@rolfbjarne agreed that would be best - not sure if that's easy to pick up the SDK build artefacts

[rolfbjarne]

We don't have to do anything to get the test assemblies if they're put in the location we already expect them.

When we consume a packaged mono, we expect files to end up in a builds/downloads/ subdirectory:

xamarin-macios/Make.config

Lines 338 to 339 in de82764

	MONO_SDK_BUILDDIR:=$(abspath $(TOP)/builds/downloads/$(basename $(MONO_FILENAME)))
	MONO_SDK_DESTDIR:=$(abspath $(TOP)/builds/downloads/$(basename $(MONO_FILENAME)))

When building from source, those variables point to external/mono/sdks/builds and external/mono/sdks/out:

xamarin-macios/Make.config

Lines 342 to 343 in de82764

	MONO_SDK_BUILDDIR:=$(abspath $(MONO_PATH)/sdks/builds)
	MONO_SDK_DESTDIR:=$(abspath $(MONO_PATH)/sdks/out)

If the mono source build puts the test assemblies in the same location as they're in the mono package (which is builds/downloads/ios-release-Darwin-<MONO_HASH>/ios-bcl/monotouch/tests/*.dll, so external/mono/sdks/out/ios-bcl/monotouch/tests/*.dll), then things will just automatically work for us.

[spouliot]

That sounds a lot better strategy than ignoring them :)

[mandel-macaque]

yeah, I like @rolfbjarne approach, mono should be doing that for us :)

[mandel-macaque]

This was already fixed. I missed when, but after the mono bump, we should have no issues.