JQF fuzz testing integration

FuzzLib.scala

@@ -0,0 +1,25 @@
+// Copyright 2024-2025 DCal Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package distcompiler
+
+class FuzzLib:
+  def fillerFunction(flag: Boolean, value: Int): Int =
+    if flag then
+      if value > 100 then value * 2
+      else if value > 50 then value + 10
+      else if value > 0 then value
+      else if value > -50 then value - 5
+      else value / 2
+    else throw new RuntimeException("Found a failure case")

FuzzLibTests.scala

@@ -0,0 +1,37 @@
+// Copyright 2024-2025 DCal Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package distcompiler
+
+import edu.berkeley.cs.jqf.fuzz.Fuzz
+import edu.berkeley.cs.jqf.fuzz.JQF
+import org.junit.runner.RunWith
+import org.junit.Assert.*
+
+@RunWith(classOf[JQF])
+class FuzzLibTests:
+  private val fuzzLib = new FuzzLib()
+
+  @Fuzz
+  def simpleTest(flag: Boolean, value: Int): Unit =
+    try
+      val result = fuzzLib.fillerFunction(flag, value)
+
+      if !flag then fail("Expected exception was not thrown")
+      else if value > 0 then assertTrue("Positive value", result > 0)
+      else assertTrue("Non-positive value", result <= 0)
+    catch
+      case e: RuntimeException =>
+        assertTrue("Exception thrown when flag was true", !flag)
+        assertEquals("Found a failure case", e.getMessage)

RunFuzzLib.scala

@@ -0,0 +1,68 @@
+// Copyright 2024-2025 DCal Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package distcompiler
+
+import edu.berkeley.cs.jqf.fuzz.junit.GuidedFuzzing
+import edu.berkeley.cs.jqf.fuzz.guidance.Guidance
+import edu.berkeley.cs.jqf.fuzz.guidance.Result
+import edu.berkeley.cs.jqf.fuzz.ei.ZestGuidance
+
+import java.io.File
+import java.io.PrintStream
+import java.util.Random
+
+object RunFuzzLib {
+  def main(args: Array[String]): Unit = {
+    val testClassName = "distcompiler.FuzzLibTests"
+    val testMethod = "simpleTest"
+
+    val outputDir = new File("fuzz-output")
+
+    if (!outputDir.exists()) {
+      outputDir.mkdirs()
+    }
+
+    val guidance = new ZestGuidance(
+      testMethod, // Name of the test method
+      null, // Duration (null for unlimited time)
+      10L, // Trial limit
+      outputDir, // Output directory for results
+      new Random() // Random number generator
+    )
+
+    println(s"Running JQF test: $testClassName#$testMethod")
+    println(s"Output directory: ${outputDir.getAbsolutePath}")
+
+    val classLoader = Thread.currentThread().getContextClassLoader()
+
+    val result = GuidedFuzzing.run(
+      testClassName,
+      testMethod,
+      classLoader,
+      guidance,
+      System.out
+    )
+
+    if (result.wasSuccessful()) {
+      println("Test completed successfully without finding failures.")
+    } else {
+      println(s"Test found ${result.getFailureCount()} failures!")
+      result.getFailures().forEach { failure =>
+        println(s"Failure: ${failure.getMessage()}")
+        failure.getException().printStackTrace()
+      }
+    }
+  }
+}

project.scala

@@ -21,6 +21,7 @@
 //> using dep com.lihaoyi::ujson::4.1.0
 //> using dependency "io.github.java-diff-utils:java-diff-utils:4.15"
 //> using test.dep org.scalameta::munit:1.1.0
+//> using dep edu.berkeley.cs.jqf:jqf-fuzz:2.0
 
 //> using javaProp distcompiler.Node.assertErrorRefCorrectness=no