disable "call always fails according to method contract" in tests (IDEA-168613)

1. test might check precisely this failure
2. even if not, the test will fail anyway and the mistake will be obvious quite soon

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DataFlowInspectionBase.java

@@ -39,6 +39,7 @@ import com.intellij.codeInspection.nullable.NullableStuffInspectionBase;
 import com.intellij.lang.java.JavaLanguage;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.project.Project;
+import com.intellij.openapi.roots.ProjectFileIndex;
 import com.intellij.openapi.util.Pair;
 import com.intellij.openapi.util.WriteExternalException;
 import com.intellij.openapi.util.text.StringUtil;
@@ -401,6 +402,10 @@ public class DataFlowInspectionBase extends BaseJavaBatchLocalInspectionTool {
   private static void reportAlwaysFailingCalls(ProblemsHolder holder,
                                                DataFlowInstructionVisitor visitor,
                                                HashSet<PsiElement> reportedAnchors) {
+    if (ProjectFileIndex.SERVICE.getInstance(holder.getProject()).isInTestSourceContent(holder.getFile().getViewProvider().getVirtualFile())) {
+      return;
+    }
+
     for (PsiCall call : visitor.getAlwaysFailingCalls()) {
       PsiMethod method = call.resolveMethod();
       if (method != null && reportedAnchors.add(call)) {

java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionHeavyTest.groovy

@@ -76,4 +76,21 @@ class DataFlowInspectionHeavyTest extends JavaCodeInsightFixtureTestCase {
       public @interface Nullable {}
       """
   }
+
+  void "test no always failing calls in tests"() {
+    PsiTestUtil.addSourceRoot(myModule, myFixture.tempDirFixture.findOrCreateDir("test"), true)
+
+    myFixture.configureFromExistingVirtualFile(myFixture.addFileToProject("test/Foo.java", """
+class Foo {
+  void foo() {
+    assertTrue(false);
+  }
+  private void assertTrue(boolean b) {
+    if (!b) throw new RuntimeException();
+  }
+}
+""").virtualFile)
+    myFixture.enableInspections(new DataFlowInspection())
+    myFixture.checkHighlighting()
+  }
 }