Add the NoDuplication support for PickOneFrom() method.

tpierrain · Jan 25, 2021 · 5822caa · 5822caa
1 parent d9bf9fe
commit 5822caa
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Showing 2 changed files with 50 additions and 2 deletions.
diff --git a/Diverse.Tests/FuzzerWithoutDuplicationShould.cs b/Diverse.Tests/FuzzerWithoutDuplicationShould.cs
@@ -183,6 +183,19 @@ public void Be_able_to_pick_always_different_values_from_a_list_of_int()
             });
         }
 
+        [Test]
+        public void Be_able_to_pick_always_different_values_from_a_medium_size_list_of_int()
+        {
+            var fuzzer = new Fuzzer(noDuplication: true);
+
+            var candidates = Enumerable.Range(-10000, 10000).ToArray();
+
+            CheckThatNoDuplicationIsMadeWhileGenerating(fuzzer, candidates.LongLength, () =>
+            {
+                return fuzzer.PickOneFrom(candidates);
+            });
+        }
+
         [Test]
         public void Be_able_to_pick_always_different_values_from_a_list_of_enum()
         {
@@ -196,6 +209,21 @@ public void Be_able_to_pick_always_different_values_from_a_list_of_enum()
             });
         }
 
+        [Test]
+        public void Be_able_to_pick_different_values_from_a_list_of_string()
+        {
+            var fuzzer = new Fuzzer(884871408);
+            var rateCodes = new[] { "PRBA", "LRBAMC", "AVG1", "PRBB", "LRBA", "BBSP", "PRBA2", "LRBA2MC", "PRPH", "PBCITE_tes", "PRPH2", "PRP2N2", "PR3NS1", "PBHS", "PBSNWH", "PBTHE", "PBVPOM", "PBZOO", "PHBO", "PHBPP", "PAB01", "PHB01", "PH3P", "LH3PMC", "CAMI", "FRCAMIF", "GENERICRATECODE", "PBGGG", "PBPPBRAZIL", "PBSENIOR" };
+
+            var noDupFuzzer = fuzzer.GenerateNoDuplicationFuzzer();
+
+            CheckThatNoDuplicationIsMadeWhileGenerating(noDupFuzzer, rateCodes.Length, () =>
+            {
+                return noDupFuzzer.PickOneFrom(rateCodes);
+            });
+
+        }
+
         #endregion
 
         #region Persons
@@ -320,6 +348,8 @@ public void Be_able_to_provide_always_different_values_of_DateTime()
         }
 
         #endregion
+
+
 
         [Test]
         public void Throw_DuplicationException_with_fix_explanation_when_number_of_attempts_is_too_low()
@@ -345,7 +375,7 @@ public void Throw_DuplicationException_with_fix_explanation_when_number_of_attem
 - Increase the value of the {nameof(Fuzzer.MaxFailingAttemptsForNoDuplication)} property for your {nameof(IFuzz)} instance.");
         }
 
-        private static void CheckThatNoDuplicationIsMadeWhileGenerating<T>(Fuzzer fuzzer, long maxNumberOfElements, Func<T> fuzzingFunction)
+        private static void CheckThatNoDuplicationIsMadeWhileGenerating<T>(IFuzz fuzzer, long maxNumberOfElements, Func<T> fuzzingFunction)
         {
             var returnedElements = new HashSet<T>(); //T
             for (var i = 0; i < maxNumberOfElements; i++)

diff --git a/Diverse/Fuzzer.cs b/Diverse/Fuzzer.cs
@@ -673,12 +673,30 @@ public T PickOneFrom<T>(IList<T> candidates)
             {
                 return GenerateWithoutDuplication<T>(CaptureCurrentMethod(), HashArguments(candidates),
                     MaxFailingAttemptsForNoDuplication, 
-                    standardGenerationFunction: (safeFuzzer) => safeFuzzer.PickOneFrom(candidates));
+                    standardGenerationFunction: (safeFuzzer) => safeFuzzer.PickOneFrom(candidates),
+                    lastChanceGenerationFunction: alreadyProvidedSortedSet => LastChanceToFindNotAlreadyPickedValue(alreadyProvidedSortedSet, candidates, this));
             }
 
             return _collectionFuzzer.PickOneFrom(candidates);
         }
 
+        private static Maybe<T> LastChanceToFindNotAlreadyPickedValue<T>(SortedSet<object> alreadyProvidedValues, IList<T> candidates, IFuzz fuzzer)
+        {
+            var allPossibleValues = candidates.ToArray();
+
+            var remainingCandidates = allPossibleValues.Except<T>(alreadyProvidedValues.Cast<T>()).ToArray();
+
+            if (remainingCandidates.Any())
+            {
+                var index = fuzzer.GenerateInteger(0, remainingCandidates.Length - 1);
+                var pickOneFrom = remainingCandidates[index];
+
+                return new Maybe<T>(pickOneFrom);
+            }
+
+            return new Maybe<T>();
+        }
+
         #endregion
 
         #region DateTimeFuzzer