diff --git a/Canon.Tests/GrammarParserTests/SimpleGrammarWithEmptyTests.cs b/Canon.Tests/GrammarParserTests/SimpleGrammarWithEmptyTests.cs
new file mode 100644
index 0000000..bbf58a1
--- /dev/null
+++ b/Canon.Tests/GrammarParserTests/SimpleGrammarWithEmptyTests.cs
@@ -0,0 +1,129 @@
+using Canon.Core.Enums;
+using Canon.Core.GrammarParser;
+using Xunit.Abstractions;
+
+namespace Canon.Tests.GrammarParserTests;
+
+public class SimpleGrammarWithEmptyTests(ITestOutputHelper testOutputHelper)
+{
+    /// <summary>
+    /// 带有空产生式的简单语法(课后题4.18)
+    /// S -> A
+    /// A -> BA | ε
+    /// B -> aB | b
+    /// 为了方便测试指定
+    /// A ProgramStruct
+    /// B ProgramBody
+    /// a Identifier
+    /// b Identifier
+    /// </summary>
+    // private readonly ITestOutputHelper _testOutputHelper;
+
+    private readonly ITestOutputHelper _testOutputHelper = testOutputHelper;
+
+    private static readonly Dictionary<NonTerminator, List<List<TerminatorBase>>> s_simpleGrammar = new()
+    {
+        {
+            new NonTerminator(NonTerminatorType.StartNonTerminator), [
+                [new NonTerminator(NonTerminatorType.ProgramStruct)]
+            ]
+        },
+        {
+            new NonTerminator(NonTerminatorType.ProgramStruct), [
+                [
+                    new NonTerminator(NonTerminatorType.ProgramBody),
+                    new NonTerminator(NonTerminatorType.ProgramStruct)
+                ],
+                []
+            ]
+        },
+        {
+            new NonTerminator(NonTerminatorType.ProgramBody), [
+                [
+                    Terminator.IdentifierTerminator,
+                    new NonTerminator(NonTerminatorType.ProgramBody)
+                ],
+                [Terminator.IdentifierTerminator]
+            ]
+        }
+    };
+
+    [Fact]
+    public void FirstSetTest()
+    {
+        GrammarBuilder builder = new()
+        {
+            Generators = s_simpleGrammar, Begin = new NonTerminator(NonTerminatorType.StartNonTerminator)
+        };
+
+        builder.Build();
+
+        Assert.Contains(builder.FirstSet, pair =>
+            pair.Key == new NonTerminator(NonTerminatorType.StartNonTerminator));
+        Assert.Contains(builder.FirstSet, pair =>
+            pair.Key == new NonTerminator(NonTerminatorType.ProgramStruct));
+        Assert.Contains(builder.FirstSet, pair =>
+            pair.Key == new NonTerminator(NonTerminatorType.ProgramBody));
+
+        foreach (HashSet<Terminator> terminators in builder.FirstSet.Values)
+        {
+            Assert.Single(terminators);
+            Assert.Contains(Terminator.IdentifierTerminator, terminators);
+        }
+    }
+
+    [Fact]
+    public void StatsTest()
+    {
+        GrammarBuilder builder = new()
+        {
+            Generators = s_simpleGrammar, Begin = new NonTerminator(NonTerminatorType.StartNonTerminator)
+        };
+
+        Grammar grammar = builder.Build();
+
+        Assert.Equal(6, builder.Automation.Count);
+
+        Assert.Contains(new NonTerminator(NonTerminatorType.ProgramStruct), grammar.BeginState.Transformer.Keys);
+        Assert.Contains(new NonTerminator(NonTerminatorType.ProgramBody), grammar.BeginState.Transformer.Keys);
+        Assert.Contains(Terminator.IdentifierTerminator, grammar.BeginState.Transformer.Keys);
+        Assert.Equal(7, grammar.BeginState.Expressions.Count);
+        _testOutputHelper.WriteLine("--- 0 ---");
+        _testOutputHelper.WriteLine(grammar.BeginState.ToString());
+
+        LrState state1 =
+            grammar.BeginState.Transformer[new NonTerminator(NonTerminatorType.ProgramStruct)];
+        Assert.Single(state1.Expressions);
+        _testOutputHelper.WriteLine("--- 1 ---");
+        _testOutputHelper.WriteLine(state1.ToString());
+
+        LrState state2 =
+            grammar.BeginState.Transformer[new NonTerminator(NonTerminatorType.ProgramBody)];
+        Assert.Contains(new NonTerminator(NonTerminatorType.ProgramStruct), state2.Transformer.Keys);
+        Assert.Contains(new NonTerminator(NonTerminatorType.ProgramBody), state2.Transformer.Keys);
+        Assert.Contains(Terminator.IdentifierTerminator, state2.Transformer.Keys);
+        Assert.Equal(7, state2.Expressions.Count);
+        _testOutputHelper.WriteLine("--- 2 ---");
+        _testOutputHelper.WriteLine(state2.ToString());
+
+        LrState state3 =
+            grammar.BeginState.Transformer[Terminator.IdentifierTerminator];
+        Assert.Contains(new NonTerminator(NonTerminatorType.ProgramBody), state3.Transformer.Keys);
+        Assert.Contains(Terminator.IdentifierTerminator, state3.Transformer.Keys);
+        Assert.Equal(8, state3.Expressions.Count);
+        _testOutputHelper.WriteLine("--- 3 ---");
+        _testOutputHelper.WriteLine(state3.ToString());
+
+        LrState state4 = state2.Transformer[new NonTerminator(NonTerminatorType.ProgramStruct)];
+        Assert.Empty(state4.Transformer);
+        Assert.Single(state4.Expressions);
+        _testOutputHelper.WriteLine("--- 4 ---");
+        _testOutputHelper.WriteLine(state4.ToString());
+
+        LrState state5 = state3.Transformer[new NonTerminator(NonTerminatorType.ProgramBody)];
+        Assert.Empty(state5.Transformer);
+        Assert.Equal(2, state5.Expressions.Count);
+        _testOutputHelper.WriteLine("--- 5 ---");
+        _testOutputHelper.WriteLine(state5.ToString());
+    }
+}