Add unit test runner

.circleci/run.sh

@@ -173,7 +173,7 @@ check_clean_git()
 check_run_individual()
 {
     local build_path=generated/linux/release/$MODEL
-	"${build_path}/dmd"  -i -run ./test/run.d test/runnable/template2962.d ./test/compilable/test14275.d
+    "${build_path}/dmd" -I./test -i -run ./test/run.d test/runnable/template2962.d ./test/compilable/test14275.d
 }
 
 # Checks the D build.d script

dub.sdl

@@ -33,19 +33,14 @@ subPackage {
   preGenerateCommands `
     "$${DUB_EXE}" \
     --arch=$${DUB_ARCH} \
+    --compiler=$${DC} \
     --single "$${DUB_PACKAGE_DIR}config.d" \
     -- "$${DUB_PACKAGE_DIR}generated/dub" \
     "$${DUB_PACKAGE_DIR}VERSION" \
     /etc
    ` platform="posix"
 
-  preGenerateCommands `
-    "%DUB_EXE%" ^
-    --arch=%DUB_ARCH% ^
-    --single "%DUB_PACKAGE_DIR%config.d" ^
-    -- "%DUB_PACKAGE_DIR%generated/dub" ^
-    "%DUB_PACKAGE_DIR%VERSION"
-  ` platform="windows"
+  preGenerateCommands `"%DUB_EXE%" --arch=%DUB_ARCH% --compiler="%DC%" --single "%DUB_PACKAGE_DIR%config.d" -- "%DUB_PACKAGE_DIR%generated/dub" "%DUB_PACKAGE_DIR%VERSION"` platform="windows"
 
   stringImportPaths "generated/dub"
 

test/Makefile

@@ -158,7 +158,11 @@ $(RESULTS_DIR)/.created:
 	$(QUIET)if [ ! -d $(RESULTS_DIR)/fail_compilation ]; then mkdir $(RESULTS_DIR)/fail_compilation; fi
 	$(QUIET)touch $(RESULTS_DIR)/.created
 
-run_tests: start_runnable_tests start_compilable_tests start_fail_compilation_tests
+run_tests: unit_tests start_runnable_tests start_compilable_tests start_fail_compilation_tests
+
+unit_tests: $(RESULTS_DIR)/unit_test_runner$(EXE)
+	@echo "Running unit tests"
+	$<
 
 run_runnable_tests: $(runnable_test_results)
 
@@ -193,3 +197,9 @@ $(RESULTS_DIR)/sanitize_json$(EXE): tools/sanitize_json.d $(RESULTS_DIR)/.create
 	@echo "PIC: '$(PIC_FLAG)'"
 	$(DMD) -conf= $(MODEL_FLAG) $(DEBUG_FLAGS) -od$(RESULTS_DIR) -of$(RESULTS_DIR)$(DSEP)sanitize_json$(EXE) -i $<
 
+$(RESULTS_DIR)/unit_test_runner$(EXE): tools/unit_test_runner.d $(RESULTS_DIR)/.created | $(DMD)
+	@echo "Building unit_test_runner tool"
+	@echo "OS: '$(OS)'"
+	@echo "MODEL: '$(MODEL)'"
+	@echo "PIC: '$(PIC_FLAG)'"
+	$(DMD) -conf= $(MODEL_FLAG) $(DEBUG_FLAGS) -od$(RESULTS_DIR) -of$(RESULTS_DIR)$(DSEP)unit_test_runner$(EXE) -i $<

test/README.md

@@ -65,6 +65,64 @@ Note:
 - `AUTO_UPDATE` doesn't work with tests that have multiple `TEST_OUTPUT` segments
 - `AUTO_UPDATE` can be set as an environment variable or as Makefile-like argument assignment
 
+### Running the Unit Tests
+
+The unit tests will automatically run when all tests are run using `./run.d` or
+`make`. To only run the unit tests the `./run.d unit_tests` command can be used.
+For a more finer grain control over the unit tests the `./run.d -u` command can
+be used:
+
+To run all unit tests:
+
+```sh
+./run.d -u
+```
+
+To only run the unit tests in one or more specific files:
+
+```sh
+./run.d -u unit/deinitialization.d
+```
+
+To only run a subset of the unit tests in a single file:
+
+```sh
+./run.d -u unit/deinitialization.d --filter Expression
+```
+
+In the above example, the `--filter` flag will filter to only run the tests with
+a UDA matching the given value, in this case `Expression`.
+
+```d
+@("Target.deinitialize")
+unittest {}
+
+@("Expression.deinitialize")
+unittest {}
+```
+
+Of the above unit tests, only the second one will be run, since
+`--filter Expression` was specified.
+
+The `--filter` flag works when no files are specified as well.
+
+## Types of Tests
+
+There are two types of tests in the DMD test suite:
+
+* **End-to-end test**. These are tests that invokes the compiler as an external
+process in some kind of way. Then it asserts either the exit code or the output
+of the compiler. These tests are located in `compilable`, `fail_compilation` and
+`runnable`.
+
+* **Unit tests**. These tests are more of a unit test, integration or
+functional style tests. These tests are using the compiler as a library. They
+are more flexible because they can assert state internal to the compiler which
+the end-to-end tests would never have access to. The unit test runner will
+compile all files in the `unit` directory into a single executable and run the
+tests. This should make it quick to run the tests since only a single process
+need to be started.
+
 Makefile targets
 ----------------
 
@@ -74,6 +132,7 @@ Makefile targets
     run_runnable_tests:         run just the runnable tests
     run_compilable_tests:       run just the compilable tests
     run_fail_compilation_tests: run just the fail compilation tests
+    unit_test:                  run all unit tests (those in the "unit" directory)
 
     quick:              run all tests with no default permuted args
                         (individual test specified options still honored)