test: add test for template substitution of return (#1391)

* test SubstitionVisitor replace of return

* fix contract description

src/test/java/spoon/test/template/TemplateReplaceReturnTest.java

@@ -0,0 +1,39 @@
+package spoon.test.template;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.File;
+
+import org.junit.Test;
+
+import spoon.Launcher;
+import spoon.OutputType;
+import spoon.reflect.code.CtBlock;
+import spoon.reflect.declaration.CtClass;
+import spoon.reflect.factory.Factory;
+import spoon.support.compiler.FileSystemFile;
+import spoon.test.template.testclasses.ReturnReplaceTemplate;
+import spoon.testing.utils.ModelUtils;
+
+public class TemplateReplaceReturnTest {
+
+	@Test
+	public void testReturnReplaceTemplate() throws Exception {
+		//contract: the template engine supports replace of `return _param_.S()` by `<CtBlock>`
+		Launcher launcher = new Launcher();
+		launcher.addTemplateResource(new FileSystemFile("./src/test/java/spoon/test/template/testclasses/ReturnReplaceTemplate.java"));
+
+		launcher.buildModel();
+		Factory factory = launcher.getFactory();
+
+		CtBlock<String> model = (CtBlock) factory.Class().get(ReturnReplaceTemplate.class).getMethod("sample").getBody();
+
+		CtClass<?> resultKlass = factory.Class().create(factory.Package().getOrCreate("spoon.test.template"), "ReturnReplaceResult");
+		new ReturnReplaceTemplate(model).apply(resultKlass);
+		assertEquals("{ { if (((java.lang.System.currentTimeMillis()) % 2L) == 0) { return \"Panna\"; }else { return \"Orel\"; } }}", resultKlass.getMethod("method").getBody().toString().replaceAll("[\\r\\n\\t]+", "").replaceAll("\\s{2,}", " "));
+		launcher.setSourceOutputDirectory(new File("./target/spooned/"));
+		launcher.getModelBuilder().generateProcessedSourceFiles(OutputType.CLASSES);
+		ModelUtils.canBeBuilt(new File("./target/spooned/spoon/test/template/ReturnReplaceResult.java"), 8);
+	}
+
+}

src/test/java/spoon/test/template/testclasses/ReturnReplaceTemplate.java

@@ -0,0 +1,29 @@
+package spoon.test.template.testclasses;
+
+import spoon.reflect.code.CtBlock;
+import spoon.template.ExtensionTemplate;
+import spoon.template.Local;
+import spoon.template.TemplateParameter;
+
+public class ReturnReplaceTemplate extends ExtensionTemplate {
+
+	public String method() throws Throwable {
+		return _statement_.S();
+	}
+
+	TemplateParameter<String> _statement_;
+
+	@Local
+	public ReturnReplaceTemplate(CtBlock<String> statement) {
+		this._statement_ = statement;
+	}
+
+	@Local
+	String sample() {
+		if(System.currentTimeMillis()%2L==0) {
+			return "Panna";
+		} else {
+			return "Orel";
+		}
+	}
+}