add test coverage for direct object finder

src/UglyToad.PdfPig.Tests/Parser/Parts/DirectObjectFinderTests.cs

@@ -0,0 +1,106 @@
+namespace UglyToad.PdfPig.Tests.Parser.Parts
+{
+    using System;
+    using Exceptions;
+    using PdfPig.Parser.Parts;
+    using PdfPig.Tokens;
+    using Tokens;
+    using Xunit;
+
+    public class DirectObjectFinderTests
+    {
+        private readonly TestPdfTokenScanner scanner = new TestPdfTokenScanner();
+
+        [Fact]
+        public void TryGetCanFollowMultipleReferenceLinks()
+        {
+            var reference1 = new IndirectReference(7, 0);
+            var reference2 = new IndirectReference(9, 0);
+
+            scanner.Objects[reference1] = new ObjectToken(10, reference1, new IndirectReferenceToken(reference2));
+            scanner.Objects[reference2] = new ObjectToken(12, reference2, new NumericToken(69));
+
+            Assert.True(DirectObjectFinder.TryGet(new IndirectReferenceToken(reference1), scanner, out NumericToken result));
+
+            Assert.Equal(69, result.Int);
+        }
+
+        [Fact]
+        public void GetCanFollowMultipleReferenceLinks()
+        {
+            var reference1 = new IndirectReference(7, 0);
+            var reference2 = new IndirectReference(9, 0);
+
+            scanner.Objects[reference1] = new ObjectToken(10, reference1, new IndirectReferenceToken(reference2));
+            scanner.Objects[reference2] = new ObjectToken(12, reference2, new NumericToken(69));
+
+            var result = DirectObjectFinder.Get<NumericToken>(reference1, scanner);
+
+            Assert.Equal(69, result.Int);
+        }
+
+        [Fact]
+        public void GetTokenCanFollowMultipleReferenceLinks()
+        {
+            var reference1 = new IndirectReference(7, 0);
+            var reference2 = new IndirectReference(9, 0);
+
+            scanner.Objects[reference1] = new ObjectToken(10, reference1, new IndirectReferenceToken(reference2));
+            scanner.Objects[reference2] = new ObjectToken(12, reference2, new NumericToken(69));
+
+            var result = DirectObjectFinder.Get<NumericToken>(new IndirectReferenceToken(reference1), scanner);
+
+            Assert.Equal(69, result.Int);
+        }
+
+        [Fact]
+        public void GetReturnsSingleItemFromArray()
+        {
+            var reference = new IndirectReference(10, 0);
+
+            const string expected = "Goopy";
+            scanner.Objects[reference] = new ObjectToken(10, reference, new ArrayToken(new []
+            {
+                new StringToken(expected)
+            }));
+
+            var result = DirectObjectFinder.Get<StringToken>(reference, scanner);
+
+            Assert.Equal(expected, result.Data);
+        }
+
+        [Fact]
+        public void GetFollowsSingleIndirectReferenceFromArray()
+        {
+            var reference = new IndirectReference(10, 0);
+            var reference2 = new IndirectReference(69, 0);
+
+            const string expected = "Goopy";
+            scanner.Objects[reference] = new ObjectToken(10, reference, new ArrayToken(new[]
+            {
+                new IndirectReferenceToken(reference2) 
+            }));
+
+            scanner.Objects[reference2] = new ObjectToken(69, reference2, new StringToken(expected));
+
+            var result = DirectObjectFinder.Get<StringToken>(reference, scanner);
+
+            Assert.Equal(expected, result.Data);
+        }
+
+        [Fact]
+        public void GetThrowsOnInvalidArray()
+        {
+            var reference = new IndirectReference(10, 0);
+
+            scanner.Objects[reference] = new ObjectToken(10, reference, new ArrayToken(new[]
+            {
+                new NumericToken(5), new NumericToken(6), new NumericToken(0)   
+            }));
+
+            Action action = () => DirectObjectFinder.Get<StringToken>(reference, scanner);
+
+            Assert.Throws<PdfDocumentFormatException>(action);
+        }
+    }
+}

src/UglyToad.PdfPig.Tests/Tokens/TestPdfTokenScanner.cs

@@ -2,12 +2,15 @@
 namespace UglyToad.PdfPig.Tests.Tokens
 {
     using System;
+    using System.Collections.Generic;
     using PdfPig.Tokenization;
     using PdfPig.Tokenization.Scanner;
     using PdfPig.Tokens;
 
     internal class TestPdfTokenScanner : IPdfTokenScanner
     {
+        public Dictionary<IndirectReference, ObjectToken> Objects { get; }
+         = new Dictionary<IndirectReference, ObjectToken>();
         public bool MoveNext()
         {
             throw new NotImplementedException();
@@ -37,7 +40,7 @@ namespace UglyToad.PdfPig.Tests.Tokens
 
         public ObjectToken Get(IndirectReference reference)
         {
-            throw new NotImplementedException();
+            return Objects[reference];
         }
     }
 }