Initial commit

Numbers.Test/NumberString/DigitEnumeratorTests.cs

@@ -0,0 +1,81 @@
+using Numbers.NumberString;
+
+namespace Numbers.Test.NumberString;
+
+public sealed class DigitEnumeratorTests
+{
+    [Fact]
+    public void MoveNext_NoMoreDigits()
+    {
+        var enumerator = new DigitEnumerator("abc");
+
+        enumerator.MoveNext().Should().BeFalse();
+    }
+
+    [Fact]
+    public void MoveNext_MoreDigits()
+    {
+        var enumerator = new DigitEnumerator("abc123");
+
+        enumerator.MoveNext().Should().BeTrue();
+    }
+
+    [Theory]
+    [MemberData(nameof(EnumeratorTestData))]
+    public void Current_CorrectDigit(string input, int moveSteps, int expectedDigit)
+    {
+        var enumerator = new DigitEnumerator(input);
+
+        enumerator.Current.Should().Be(-1, "enumerator not moved yet");
+        for (var i = 0; i < moveSteps; i++)
+        {
+            enumerator.MoveNext();
+        }
+
+        enumerator.Current.Should().Be(expectedDigit);
+    }
+
+    [Fact]
+    public void Reset()
+    {
+        var enumerator = new DigitEnumerator("abc123");
+        enumerator.MoveNext();
+        enumerator.MoveNext();
+
+        enumerator.Reset();
+        enumerator.MoveNext();
+
+        enumerator.Current.Should().Be(1);
+    }
+
+    [Fact]
+    public void Interface()
+    {
+        var enumerator = new DigitEnumerator("abc123");
+
+        enumerator.Should().BeAssignableTo<IEnumerator<int>>();
+    }
+
+    public static TheoryData<string, int, int> EnumeratorTestData() =>
+        new()
+        {
+            { "abc132", 1, 1 },
+            { "abc132", 2, 3 },
+            { "abc132", 3, 2 },
+            { "1abc23", 1, 1 },
+            { "1abc23", 2, 2 },
+            { "1abc23", 3, 3 },
+            { "a1b2c3", 1, 1 },
+            { "a1b2c3", 2, 2 },
+            { "a1b2c3", 3, 3 },
+            { "123abc", 1, 1 },
+            { "123abc", 2, 2 },
+            { "123abc", 3, 3 },
+            { "2def456", 1, 2 },
+            { "2def456", 2, 4 },
+            { "2def456", 3, 5 },
+            { "d4ef56", 1, 4 },
+            { "d4ef56", 2, 5 },
+            { "d4ef56", 3, 6 }
+        };
+}