Allow testing of just a single file (#3511)

* allow testing of just a single file

* simplify

* remove debug statements

* remove debug statements

* add comment

* add remark in Contributors guide for how to run a single test file

docs/src/contributing.md

@@ -36,11 +36,11 @@ Discussions are recommended for asking questions about (for example) the user in
 
 * Note: for small or minor changes (such as fixing a typo in documentation), the [GitHub editor](https://docs.github.com/en/github/managing-files-in-a-repository/managing-files-on-github/editing-files-in-your-repository) is super useful for forking and opening a pull request with a single click.
 
-* Write your code with love and care. In particular, conform to existing Oceananigans style and formatting conventions. For example, we love verbose and explicit variable names, use `TitleCase` for types, `snake_case` for objects, and always.put.spaces.after.commas. For formatting decisions we loosely follow the [YASGuide](https://github.com/jrevels/YASGuide). It's worth few extra minutes of our time to leave future generations with well-written, readable code.
+* Write your code with love and care. In particular, conform to existing Oceananigans style and formatting conventions. For example, we love verbose and explicit variable names, use `TitleCase` for types, `snake_case` for objects, and always,put,spaces.after.commas,or.periods. For formatting decisions we loosely follow the [YASGuide](https://github.com/jrevels/YASGuide). It's worth few extra minutes of our time to leave future generations with well-written, readable code.
 
 ## What is a "collaborator" and how can I become one?
 
-* Collaborators have permissions to review pull requests and  status allows a contributor to review pull requests in addition to opening them. Collaborators can also create branches in the main Oceananigans repository.
+* Collaborators have permissions to review pull requests and status allows a contributor to review pull requests in addition to opening them. Collaborators can also create branches in the main Oceananigans repository.
 
 * We ask that new contributors try their hand at forking Oceananigans, and opening and merging a pull request before requesting collaborator status.
 
@@ -122,12 +122,17 @@ Oceananigans or by requesting something you think is missing.
 
 * Create the development environment by opening Julia via `julia --project` then
   typing in `] instantiate`. This will install all the dependencies in the Project.toml
-  file.
+  file. Your development environment is now ready!
 
-* You can test to make sure Oceananigans works by typing in `] test`. Doing so will run all
-  the tests (and this can take a while).
+* You can test to make sure Oceananigans works by typing in `] test`. (This is equivalent to
+  `using Pkg; Pkg.test()`.) Doing so will run all the tests (and this can take a while).
+  Alternatively, you can run only one test script file by providing its name as an environment
+  variable. For example, to run the tests only from the `test_coriolis.jl` file we call:
+
+  ```
+  $ TEST_FILE=test_coriolis.jl julia --project -e"using Pkg; Pkg.test()"
+  ```
 
-Your development environment is now ready!
 
 ## Pull Requests
 

test/dependencies_for_runtests.jl

@@ -57,8 +57,6 @@ Logging.global_logger(OceananigansLogger())
 ##### Testing parameters
 #####
 
-float_types = (Float32, Float64)
-
 closures = (
     :ScalarDiffusivity,
     :ScalarBiharmonicDiffusivity,
@@ -68,15 +66,5 @@ closures = (
     :ConvectiveAdjustmentVerticalDiffusivity,
 )
 
-#####
-##### Run tests!
-#####
-
-float_types = (Float32, Float64)
-
 include("utils_for_runtests.jl")
 
-archs = test_architectures()
-
-group     = get(ENV, "TEST_GROUP", :all) |> Symbol
-test_file = get(ENV, "TEST_FILE", :none) |> Symbol

test/runtests.jl

@@ -1,5 +1,22 @@
 include("dependencies_for_runtests.jl")
 
+float_types = (Float32, Float64)
+archs = test_architectures()
+
+group     = get(ENV, "TEST_GROUP", :all) |> Symbol
+test_file = get(ENV, "TEST_FILE", :none) |> Symbol
+
+# if we are testing just a single file then group = :none
+# to skip the full test suite
+if test_file != :none
+    group = :none
+end
+
+
+#####
+##### Run tests!
+#####
+
 CUDA.allowscalar() do
 
 @testset "Oceananigans" begin