Add betterC support - fixes #1636 (#2581)

Co-authored-by: Etienne Cimon <etcimon@gmail.com>
Co-authored-by: WebFreak001 <gh@webfreak.org>

source/dub/project.d

@@ -1916,22 +1916,33 @@ alias allModules = TypeTuple!(
 
 /// The default test runner that gets used if none is provided
 private immutable DefaultTestRunnerCode = q{
-import core.runtime;
-
-void main() {
-	version (D_Coverage) {
+	version(D_BetterC) {
+		extern(C) int main() {
+			foreach (module_; allModules) {
+				foreach (unitTest; __traits(getUnitTests, module_)) {
+					unitTest();
+				}
+			}
+			import core.stdc.stdio : puts;
+			puts("All unit tests have been run successfully.");
+			return 0;
+		}
 	} else {
-		import std.stdio : writeln;
-		writeln("All unit tests have been run successfully.");
-	}
-}
-shared static this() {
-	version (Have_tested) {
-		import tested;
-		import core.runtime;
-		import std.exception;
-		Runtime.moduleUnitTester = () => true;
-		enforce(runUnitTests!allModules(new ConsoleTestResultWriter), "Unit tests failed.");
+		void main() {
+			version (D_Coverage) {
+			} else {
+				import std.stdio : writeln;
+				writeln("All unit tests have been run successfully.");
+			}
+		}
+		shared static this() {
+			version (Have_tested) {
+				import tested;
+				import core.runtime;
+				import std.exception;
+				Runtime.moduleUnitTester = () => true;
+				enforce(runUnitTests!allModules(new ConsoleTestResultWriter), "Unit tests failed.");
+			}
+		}
 	}
-}
 };

test/issue1636-betterC-dub-test.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+cd ${CURR_DIR}/issue1636-betterC-dub-test
+
+${DUB} test | grep -c "TEST_WAS_RUN" > /dev/null

test/issue1636-betterC-dub-test/.gitignore

@@ -0,0 +1,4 @@
+test
+*.o
+*.exe
+.dub

test/issue1636-betterC-dub-test/.min_frontend

@@ -0,0 +1 @@
+2.078

test/issue1636-betterC-dub-test/dub.json

@@ -0,0 +1,4 @@
+{
+	"name": "test",
+	"buildOptions": ["betterC"]
+}

test/issue1636-betterC-dub-test/source/lib.d

@@ -0,0 +1,14 @@
+import core.stdc.stdio : printf;
+
+version(D_BetterC) {} else static assert(false);
+
+int foo()
+{
+	return 2;
+}
+
+unittest
+{
+	assert(foo == 2);
+	printf("TEST_WAS_RUN\n");
+}