Improve infinite loop test cases runner

mjtest/test/exec_tests.py

@@ -17,8 +17,8 @@ class JavaExecTest(BasicSyntaxTest):
     The MiniJava compiler should behave the same as javac
     """
 
-    FILE_ENDINGS = [".java"]
-    INVALID_FILE_ENDINGS = [".inf.java"]
+    FILE_ENDINGS = [".java", ".mj"]
+    INVALID_FILE_ENDINGS = [".inf.java", ".inf.mj"]
     OUTPUT_FILE_ENDING = ".out"
     MODE = TestMode.compile_firm
 
@@ -96,11 +96,14 @@ TestCase.TEST_CASE_CLASSES[TestMode.compile_firm].append(JavaExecTest)
 
 class JavaInfiniteLoopTest(BasicSyntaxTest):
 
-    FILE_ENDINGS = [".inf.java"]
+    FILE_ENDINGS = [".inf.java", ".inf.mj"]
+    OUTPUT_FILE_ENDING = ".out"
     MODE = TestMode.compile_firm
 
     def __init__(self, env: Environment, type: str, file: str, preprocessed_file: str):
         super().__init__(env, type, file, preprocessed_file)
+        self._output_file = self.file + self.OUTPUT_FILE_ENDING
+        self._has_output_file = path.exists(self._output_file)
 
     def run(self) -> BasicTestResult:
         base_filename = path.basename(self.file).split(".")[0]
@@ -109,20 +112,31 @@ class JavaInfiniteLoopTest(BasicSyntaxTest):
         cwd = os.getcwd()
         os.chdir(tmp_dir)
         timeout = 1
+        err = ""
+        out = ""
+        out2 = ""
         try:
-            _, err, rtcode = self.env.run_mj_command(self.MODE, base_filename + ".java")
+            out2, err, rtcode = self.env.run_mj_command(self.MODE, base_filename + ".java")
             out, _, _ = self.env.run_command("./" + base_filename, timeout=timeout)
         except SigKill as kill:
             os.chdir(cwd)
             if kill.retcode == signal.SIGXCPU:
-                return BasicTestResult(self, err.decode(), 0, out.decode())
+                if self._has_output_file:
+                    out = out.decode().strip()
+                    exp_out = ""
+                    with open(self._output_file, "r") as f:
+                        exp_out = f.read().strip()
+                    if not out.startswith(exp_out):
+                        return BasicDiffTestResult(self, 1, out, err.decode(), exp_out,
+                                                   "Output doesn't start like expected")
+                return BasicTestResult(self, 0, err.decode(), out.decode())
             else:
-                return BasicTestResult(self, kill.retcode, "", "", "No timeout, got " + kill.name)
+                return BasicTestResult(self, kill.retcode, "", err.decode(), "No timeout, got " + kill.name)
         except:
             os.chdir(cwd)
             raise
         os.chdir(cwd)
-        return BasicTestResult(self, 1, "", "", "No timeout")
+        return BasicTestResult(self, 1, "", err.decode(), "No timeout")
 
 
 TestCase.TEST_CASE_CLASSES[TestMode.compile_firm].append(JavaInfiniteLoopTest)
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