Add WithStringBody() assertion.

Author: GillesTourreau

src/Testing.Azure.Functions.Http/HttpResponseDataAssertions.cs

@@ -6,6 +6,7 @@
 
 namespace PosInformatique.Testing.Azure.Functions.Http
 {
+    using System.Text;
     using System.Text.Json;
     using global::FluentAssertions;
     using global::FluentAssertions.Common;
@@ -77,5 +78,32 @@ public HttpResponseDataAssertions WithJsonBody<T>(T expectedJsonObject, JsonSeri
 
             return this;
         }
+
+        /// <summary>
+        /// Assert the content of the <see cref="HttpResponseData.Body"/> to check if it is
+        /// string encoded with the specified <paramref name="encoding"/>.
+        /// </summary>
+        /// <param name="expectedString">Expected string encoded.</param>
+        /// <param name="encoding">Encoding of the string to check. If <see langword="null"/>, the UTF-8 encoding is used.</param>
+        /// <returns>The current instance of the <see cref="HttpResponseDataAssertions"/> to continue the assertions.</returns>
+        public HttpResponseDataAssertions WithStringBody(string expectedString, Encoding? encoding = null)
+        {
+            if (encoding is null)
+            {
+                encoding = Encoding.UTF8;
+            }
+
+            var bodyStream = this.response.GetBodyStream();
+
+            using var memoryStream = new MemoryStream();
+
+            bodyStream.CopyTo(memoryStream);
+
+            var actualString = encoding.GetString(memoryStream.ToArray());
+
+            actualString.Should().Be(expectedString);
+
+            return this;
+        }
     }
 }

tests/Testing.Azure.Functions.Http.Tests/HttpResponseDataAssertionsTest.cs

@@ -6,6 +6,7 @@
 
 namespace PosInformatique.Testing.Azure.Functions.Http.Tests
 {
+    using System.Text;
     using System.Text.Json;
     using Xunit.Sdk;
 
@@ -141,5 +142,79 @@ public void WithEmptyBody_Failed()
 
             response.Body.Position.Should().Be(position);
         }
+
+        [Fact]
+        public void WithStringBody()
+        {
+            var response = new HttpResponseDataImplementation(new FunctionContextImplementation(new HttpRequestDataMock()));
+            response.Body.Write(Encoding.Unicode.GetBytes("The string"));
+
+            var assertions = new HttpResponseDataAssertions(response);
+
+            var position = response.Body.Position;
+
+            assertions.WithStringBody("The string", Encoding.Unicode)
+                .Should().BeSameAs(assertions);
+
+            response.Body.Position.Should().Be(position);
+        }
+
+        [Fact]
+        public void WithStringBody_DefaultEncoding()
+        {
+            var response = new HttpResponseDataImplementation(new FunctionContextImplementation(new HttpRequestDataMock()));
+            response.Body.Write(Encoding.UTF8.GetBytes("The string"));
+
+            var assertions = new HttpResponseDataAssertions(response);
+
+            var position = response.Body.Position;
+
+            assertions.WithStringBody("The string")
+                .Should().BeSameAs(assertions);
+
+            response.Body.Position.Should().Be(position);
+        }
+
+        [Fact]
+        public void WithStringBody_DifferentValue_Failed()
+        {
+            var response = new HttpResponseDataImplementation(new FunctionContextImplementation(new HttpRequestDataMock()));
+            response.Body.Write(Encoding.Unicode.GetBytes("The other string"));
+
+            var assertions = new HttpResponseDataAssertions(response);
+
+            var position = response.Body.Position;
+
+            var act = () =>
+            {
+                assertions.WithStringBody("The string", Encoding.Unicode);
+            };
+
+            act.Should().ThrowExactly<XunitException>()
+                .WithMessage("Expected actualString to be \"The string\" with a length of 10, but \"The other string\" has a length of 16, differs near \"oth\" (index 4).");
+
+            response.Body.Position.Should().Be(position);
+        }
+
+        [Fact]
+        public void WithStringBody_DifferentEncoding_Failed()
+        {
+            var response = new HttpResponseDataImplementation(new FunctionContextImplementation(new HttpRequestDataMock()));
+            response.Body.Write(Encoding.UTF8.GetBytes("The other string"));
+
+            var assertions = new HttpResponseDataAssertions(response);
+
+            var position = response.Body.Position;
+
+            var act = () =>
+            {
+                assertions.WithStringBody("The string", Encoding.Unicode);
+            };
+
+            act.Should().ThrowExactly<XunitException>()
+                .WithMessage("Expected actualString to be \"The string\" with a length of 10, but \"桔\u2065瑯敨\u2072瑳楲杮\" has a length of 8, differs near \"桔\u2065瑯\" (index 0).");
+
+            response.Body.Position.Should().Be(position);
+        }
     }
 }