Asset refactoring and content files

test/Microsoft.DotNet.ProjectModel.Tests/PreprocessorTests.cs

@@ -0,0 +1,53 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using FluentAssertions;
+using Xunit;
+using Microsoft.DotNet.Tools.Compiler;
+
+namespace Microsoft.DotNet.ProjectModel.Tests
+{
+    public class PreprocessorTests
+    {
+        private string Preprocess(string text, IDictionary<string, string> parameters)
+        {
+            using (var input = new MemoryStream(Encoding.UTF8.GetBytes(text)))
+            {
+                using (var output = new MemoryStream())
+                {
+                    PPFilePreprocessor.Preprocess(input, output, parameters);
+                    return Encoding.UTF8.GetString(output.ToArray());
+                }
+            }
+        }
+
+        [Theory]
+        [InlineData("$a$", "AValue")]
+        [InlineData("$a", "$a")]
+        [InlineData("a$", "a$")]
+        [InlineData("$$a$", "$a$")]
+        [InlineData("$a$$b$", "AValueBValue")]
+        [InlineData("$$a$$$$b$$", "$a$$b$")]
+
+        public void ProcessesCorrectly(string input, string output)
+        {
+            var parameters = new Dictionary<string, string>()
+            {
+                { "a", "AValue" },
+                { "b", "BValue" }
+            };
+            var result = Preprocess(input, parameters);
+            result.Should().Be(output);
+        }
+
+        [Fact]
+        public void ThrowsOnParameterNotFound()
+        {
+            var ex = Assert.Throws<InvalidOperationException>(() => Preprocess("$a$", new Dictionary<string, string>()));
+            ex.Message.Should().Contain("a");
+        }
+    }
+}