Use external test data

[nlohmann]

This PR removes the test data from this repository and downloads them from an external repository.

Closes #96
Closes #482
Closes #556
Closes #567
Closes #620
Closes #732
Closes #1066
Closes #1184
Closes #1185
Closes #1235
Closes #1497
Closes #1572
Closes #1790

[nickaein]

On a clean repo, make check command fails since download_test_data command doesn't get executed.

isaac@ubuntu$ make check
make check -C test
make[1]: Entering directory '/home/isaac/nl-json/test'
[CXX]   src/unit-bson.o
src/unit-bson.cpp:37:25: fatal error: test_data.hpp: No such file or directory
compilation terminated.
Makefile:71: recipe for target 'src/unit-bson.o' failed
make[1]: *** [src/unit-bson.o] Error 1
make[1]: Leaving directory '/home/isaac/nl-json/test'
Makefile:64: recipe for target 'check' failed
make: *** [check] Error 2
isaac@ubuntu$

[nlohmann]

On a clean repo, make check command fails since download_test_data command doesn't get executed.

I am currently moving functionality from the plain Makefile to CMake. The header is generated by CMake, and the dependency to download the test data first is only expressed in CTest.

Some more info on this: The original Makefile was written in times when the project did not use CMake. Right now, I hope that I am the only one relying on the Makefile, and I keep changing it for my only needs, sometimes hardcoding paths on my machine into it. Once this PR is merged, I would like to continue moving more functionality into CMake and thereby streamlining the whole release process which is currently a large Python project...

[nlohmann]

Also related: #1251

[nlohmann]

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🔖 Release item

This issue/PR will be part of the next release of the library. This template helps preparing the release notes.

Type

• ✨ New Feature
• 🐛 Bug Fix
• ⚡️ Improvement
• 🔨 Further Change
• 🔥 Deprecated function

Description

• Moved test data in separate repository. 17 MB / 90 MB repo size!? #96 For a header-only library you have to clone 214MB #482 Minimal repository (current size very large) #556 Need to improve ignores.. #567 [Question] When using this as git submodule, will it clone the whole thing include test data and benchmark? #620 Move test blobs to a submodule? #732 Minimal branch? #1066 CMakeLists.txt in release zips? #1184 reduce repos size #1185 Move tests to a separate repo #1235 Repository is almost 450MB #1497 A "thinner" source code tar as part of release? #1572 Unnecessary test data file in the release #1790 Use external test data #2081

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[tuananh]

Awesome! Thanks!

[Mailaender]

This has the downside that tests will now fail in Linux distribution build environments that have no internet access.

[nlohmann]

Is this a thing? I mean: having the library, having no internet connection, yet still want to execute the tests?

[Mailaender]

I had to disable the tests for https://build.opensuse.org/request/show/856756 which is not nice but also not too serious. https://build.opensuse.org/package/rdiff/home:Mailaender:branches:devel:libraries:c_c++/nlohmann_json?linkrev=base&rev=2 is my try to disable the data download modules, but it seems they don't disable the tests that depend on it, but that may more be some kind of ctest problem.