test/langtools/lib/combo/tools/javac/combo/Diagnostics.java

*** 82,10 ***
--- 82,16 ---
          return diags.stream()
                      .filter(d -> d.getKind() == Diagnostic.Kind.WARNING || d.getKind() == Diagnostic.Kind.MANDATORY_WARNING)
                      .anyMatch(d -> d.getCode().equals(key));
      }
  
+     public boolean containsWarningKey(String key, int numberOfWarnings) {
+         return diags.stream()
+                 .filter(d -> d.getKind() == Diagnostic.Kind.WARNING || d.getKind() == Diagnostic.Kind.MANDATORY_WARNING)
+                 .filter(d -> d.getCode().equals(key)).count() == numberOfWarnings;
+     }
+ 
      /** Get the error keys */
      public List<String> errorKeys() {
          return diags.stream()
                      .filter(d -> d.getKind() == Diagnostic.Kind.ERROR)
                      .map(Diagnostic::getCode)