small improvements to locating mono, node

doc/building-antlr.md

@@ -130,9 +130,12 @@ Note that ANTLR is written in itself, which is why maven downloads antlr4-4.5.ja
 
 ## Running test subsets
 
+*From the `runtime-testsuite` dir*
+
 ### Run one test group across targets
 
 ```bash
+$ cd runtime-testsuite
 $ mvn -Dtest=TestParserExec test
 -------------------------------------------------------
  T E S T S

runtime-testsuite/test/org/antlr/v4/test/runtime/csharp/BaseCSharpTest.java

@@ -494,7 +494,7 @@ public class BaseCSharpTest implements RuntimeTestSupport, SpecialRuntimeTestAss
 	}
 
 	private String locateTool(String tool) {
-		String[] roots = { "/usr/bin/", "/usr/local/bin/" };
+		String[] roots = { "/opt/local/bin/", "/usr/bin/", "/usr/local/bin/" };
 		for(String root : roots) {
 			if(new File(root + tool).exists())
 				return root + tool;

runtime-testsuite/test/org/antlr/v4/test/runtime/javascript/node/BaseNodeTest.java

@@ -450,21 +450,35 @@ public class BaseNodeTest implements RuntimeTestSupport {
 		return null;
 	}
 
+	private boolean canExecute(String tool) {
+		try {
+			ProcessBuilder builder = new ProcessBuilder(tool, "--version");
+			builder.redirectErrorStream(true);
+			Process process = builder.start();
+			StreamVacuum vacuum = new StreamVacuum(process.getInputStream());
+			vacuum.start();
+			process.waitFor();
+			vacuum.join();
+			return process.exitValue() == 0;
+		}
+		catch (Exception e) {
+			;
+		}
+		return false;
+	}
+
 	private String locateNodeJS() {
 		// typically /usr/local/bin/node
 		String propName = "antlr-javascript-nodejs";
 		String prop = System.getProperty(propName);
-		if (prop == null || prop.length() == 0) {
-			prop = locateTool("nodejs"); // seems to be nodejs on ubuntu
+
+		if ( prop!=null && prop.length()!=0 ) {
+			return prop;
 		}
-		if ( prop==null ) {
-			prop = locateTool("node"); // seems to be node on mac
+		if (canExecute("nodejs")) {
+			return "nodejs"; // nodejs on Debian without node-legacy package
 		}
-		File file = new File(prop);
-		if (!file.exists()) {
-			throw new RuntimeException("Missing system property:" + propName);
-		}
-		return prop;
+		return "node"; // everywhere else
 	}
 
 	private String locateRuntime() {

runtime-testsuite/test/org/antlr/v4/test/runtime/python/BasePythonTest.java

@@ -592,10 +592,11 @@ public abstract class BasePythonTest implements RuntimeTestSupport {
 	}
 
 	private String locateTool(String tool) {
-		String[] roots = { "/usr/bin/", "/usr/local/bin/" };
+		String[] roots = { "/opt/local/bin", "/usr/bin/", "/usr/local/bin/" };
 		for(String root : roots) {
-			if(new File(root + tool).exists())
-				return root + tool;
+			if(new File(root + tool).exists()) {
+				return root+tool;
+			}
 		}
 		throw new RuntimeException("Could not locate " + tool);
 	}