Add test coverage for OccurrenceConstraint

Tests/FluentAssertions.Specs/OccurrenceConstraintSpecs.cs

@@ -0,0 +1,107 @@
+using System;
+using FluentAssertions.Execution;
+using Xunit;
+using Xunit.Sdk;
+
+namespace FluentAssertions.Specs
+{
+    public class OccurrenceConstraintSpecs
+    {
+        public static object[][] PassingConstraints() => new object[][]
+        {
+            new object[] { AtLeast.Once(), 1 },
+            new object[] { AtLeast.Once(), 2 },
+            new object[] { AtLeast.Twice(), 2 },
+            new object[] { AtLeast.Twice(), 3 },
+            new object[] { AtLeast.Thrice(), 3 },
+            new object[] { AtLeast.Thrice(), 4 },
+            new object[] { AtLeast.Times(4), 4 },
+            new object[] { AtLeast.Times(4), 5 },
+
+            new object[] { AtMost.Once(), 0 },
+            new object[] { AtMost.Once(), 1 },
+            new object[] { AtMost.Twice(), 1 },
+            new object[] { AtMost.Twice(), 2 },
+            new object[] { AtMost.Thrice(), 2 },
+            new object[] { AtMost.Thrice(), 3 },
+            new object[] { AtMost.Times(4), 3 },
+            new object[] { AtMost.Times(4), 4 },
+
+            new object[] { Exactly.Once(), 1 },
+            new object[] { Exactly.Twice(), 2 },
+            new object[] { Exactly.Thrice(), 3 },
+            new object[] { Exactly.Times(4), 4 },
+
+            new object[] { LessThan.Twice(), 1 },
+            new object[] { LessThan.Thrice(), 2 },
+            new object[] { LessThan.Times(4), 3 },
+
+            new object[] { MoreThan.Once(), 2 },
+            new object[] { MoreThan.Twice(), 3 },
+            new object[] { MoreThan.Thrice(), 4 },
+            new object[] { MoreThan.Times(4), 5 },
+        };
+
+        [Theory]
+        [MemberData(nameof(PassingConstraints))]
+        public void Occurrence_constraint_passes(OccurrenceConstraint constraint, int occurrences)
+        {
+            // Act / Assert
+            Execute.Assertion
+                .ForConstraint(constraint, occurrences)
+                .FailWith("");
+        }
+
+        public static object[][] FailingConstraints() => new object[][]
+        {
+            new object[] { AtLeast.Once(), 0 },
+            new object[] { AtLeast.Twice(), 1 },
+            new object[] { AtLeast.Thrice(), 2 },
+            new object[] { AtLeast.Times(4), 3 },
+
+            new object[] { AtMost.Once(), 2 },
+            new object[] { AtMost.Twice(), 3 },
+            new object[] { AtMost.Thrice(), 4 },
+            new object[] { AtMost.Times(4), 5 },
+
+            new object[] { Exactly.Once(), 0 },
+            new object[] { Exactly.Once(), 2 },
+            new object[] { Exactly.Twice(), 1 },
+            new object[] { Exactly.Twice(), 3 },
+            new object[] { Exactly.Thrice(), 2 },
+            new object[] { Exactly.Thrice(), 4 },
+            new object[] { Exactly.Times(4), 3 },
+            new object[] { Exactly.Times(4), 5 },
+
+            new object[] { LessThan.Twice(), 2 },
+            new object[] { LessThan.Twice(), 3 },
+            new object[] { LessThan.Thrice(), 3 },
+            new object[] { LessThan.Thrice(), 4 },
+            new object[] { LessThan.Times(4), 4 },
+            new object[] { LessThan.Times(4), 5 },
+
+            new object[] { MoreThan.Once(), 0 },
+            new object[] { MoreThan.Once(), 1 },
+            new object[] { MoreThan.Twice(), 1 },
+            new object[] { MoreThan.Twice(), 2 },
+            new object[] { MoreThan.Thrice(), 2 },
+            new object[] { MoreThan.Thrice(), 3 },
+            new object[] { MoreThan.Times(4), 3 },
+            new object[] { MoreThan.Times(4), 4 },
+        };
+
+        [Theory]
+        [MemberData(nameof(FailingConstraints))]
+        public void Occurrence_constraint_fails(OccurrenceConstraint constraint, int occurrences)
+        {
+            // Act
+            Action act = () => Execute.Assertion
+                .ForConstraint(constraint, occurrences)
+                .FailWith($"Expected occurrence to be {constraint.Mode} {constraint.ExpectedCount}, but it was {occurrences}");
+
+            // Assert
+            act.Should().Throw<XunitException>()
+                .WithMessage("Expected occurrence to be *, but it was *");
+        }
+    }
+}