refactor readme files: in julia tests
ADD
tests/julia/README.md
+# Overview of tests for the julia buildpack
+
+## Tested configuration files
+
+- [`Project.toml`](https://repo2docker.readthedocs.io/en/latest/config_files.html#project-toml-install-a-julia-environment)
+- [`REQUIRE`](https://repo2docker.readthedocs.io/en/latest/config_files.html#require-install-a-julia-environment-legacy)
+- [`requirements.txt`](https://repo2docker.readthedocs.io/en/latest/config_files.html#requirements-txt-install-a-python-environment)
+
+## Test folders
+
+### project
+
+- Tests use of a `Project.toml` file for Julia, using the repo2docker default
+ version of Julia as specified in `julia_project.py`.
+
+### project-1.0.2
+
+- Tests use of a `Project.toml` file for Julia, using a version of Julia
+ specified via `julia = "=1.0.2"` in `Project.toml`'s `[compat]` section.
+
+### require
+
+- Tests use of a `REQUIRE` file for Julia, using the repo2docker default version
+ of Julia as specified in `julia_require.py`. Note that this is default version
+ is currently 0.6.4!
+
+- Starting with Julia v0.7 and up, the package manager has changed, so this
+ tests that the Julia version below that can be installed correctly as well.
+
+### require-1-requirements-file
+
+- Tests use of a `REQUIRE` file for Julia, using a major version version
+ specification. Note that this major version specification is currently
+ resolving to a pinned minor and patch version as declared in
+ `julia_require.py`.
+
+- Test use of a `requirements.txt` file, where it is expected to be respected
+ alongside the `REQUIRE` file.

DELETE
tests/julia/project-1.0.2/README.rst
-Julia - Project.toml
---------------------
-
-Test a Project.toml file with a specified version for julia.

DELETE
tests/julia/project/README.rst
-Julia - Project.toml
---------------------
-
-This tests a Project.toml file for julia, using the repo2docker default version
-of julia as specified in ``julia_project.py``.

RENAME
tests/julia/require-1-requirements/REQUIRE
tests/julia/require-1-requirements-file/REQUIRE
RENAME
tests/julia/require-1-requirements/requirements.txt
tests/julia/require-1-requirements-file/requirements.txt
RENAME
tests/julia/require-1-requirements/verify
tests/julia/require-1-requirements-file/verify
DELETE
tests/julia/require-1-requirements/README.rst
-Julia - REQUIRE, and a requirements.txt file
---------------------------------------------
-
-This tests a REQUIRE file for julia, using the repo2docker default version of
-julia as specified in ``julia_require.py``.
-
-This tests the use of the legacy REQUIRE file together with the an
-``requirements.txt`` file.

DELETE
tests/julia/require/README.rst
-Julia - REQUIRE, and use of old package manager
------------------------------------------------
-
-This tests a REQUIRE file for julia, using the repo2docker default version of
-julia as specified in ``julia_require.py``. Note that this is default version is
-0.6.4!
-
-Starting with Julia v0.7 and up, the package manager has changed, so this tests
-that the Julia version below that can be installed correctly as well.

refactor readme files: in julia tests