Add tests for controller. Put in contigency for when an item isn't found.

src/Robware.Api.Blog.Tests/BlogControllerTests.cs

@@ -0,0 +1,52 @@
+using System.Threading.Tasks;
+using FluentAssertions;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
+using NSubstitute;
+using NSubstitute.ExceptionExtensions;
+using Robware.Api.Blog.Controllers;
+using Robware.Blog;
+using Robware.Data;
+using Xunit;
+
+namespace Robware.Api.Blog.Tests {
+	public class BlogControllerTests {
+		[Fact]
+		public async Task Get_WithUrl_ReturnsBlogPost() {
+			var logger = Substitute.For<ILogger<BlogController>>();
+			var repo = Substitute.For<IBlogRepository>();
+
+			repo.GetPostByUrlAsync("url").Returns(new BlogPost());
+
+			var expectation = new BlogPost();
+
+			var controller = new BlogController(logger, repo);
+			(await controller.Get("url")).Value.Should().BeEquivalentTo(expectation);
+		}
+
+		[Fact]
+		public async Task Get_WithId_ReturnsBlogPost() {
+			var logger = Substitute.For<ILogger<BlogController>>();
+			var repo = Substitute.For<IBlogRepository>();
+
+			repo.GetPostByIdAsync(1).Returns(new BlogPost());
+
+			var expectation = new BlogPost();
+
+			var controller = new BlogController(logger, repo);
+			(await controller.Get("1")).Value.Should().BeEquivalentTo(expectation);
+		}
+
+		[Fact]
+		public async Task Get_WithInvalidUrl_Returns404() {
+			var logger = Substitute.For<ILogger<BlogController>>();
+			var repo = Substitute.For<IBlogRepository>();
+
+			repo.GetPostByUrlAsync("url").Throws(new ItemNotFoundException("", null));
+
+			var controller = new BlogController(logger, repo);
+			(await controller.Get("url")).Result.Should().BeOfType<NotFoundObjectResult>();
+
+		}
+	}
+}

src/Robware.Api.Blog.Tests/Robware.Api.Blog.Tests.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="FluentAssertions" Version="5.10.3" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.2.0" />
+    <PackageReference Include="NSubstitute" Version="4.2.1" />
+    <PackageReference Include="xunit" Version="2.4.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />
+    <PackageReference Include="coverlet.collector" Version="1.0.1" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Robware.Api.Blog\Robware.Api.Blog.csproj" />
+  </ItemGroup>
+
+</Project>

src/Robware.Api.Blog.sln

@@ -16,6 +16,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		..\.editorconfig = ..\.editorconfig
 	EndProjectSection
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Robware.Api.Blog.Tests", "Robware.Api.Blog.Tests\Robware.Api.Blog.Tests.csproj", "{54DEC274-5F28-42FB-9B60-1E4BAF3D7BF9}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -38,6 +40,10 @@ Global
 		{EEB41C17-B61C-451A-9C72-2B405DC42743}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{EEB41C17-B61C-451A-9C72-2B405DC42743}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{EEB41C17-B61C-451A-9C72-2B405DC42743}.Release|Any CPU.Build.0 = Release|Any CPU
+		{54DEC274-5F28-42FB-9B60-1E4BAF3D7BF9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{54DEC274-5F28-42FB-9B60-1E4BAF3D7BF9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{54DEC274-5F28-42FB-9B60-1E4BAF3D7BF9}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{54DEC274-5F28-42FB-9B60-1E4BAF3D7BF9}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/Robware.Api.Blog/Controllers/BlogController.cs

@@ -3,6 +3,7 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Logging;
 using Robware.Blog;
+using Robware.Data;
 
 namespace Robware.Api.Blog.Controllers {
 	[ApiController]
@@ -16,14 +17,20 @@ namespace Robware.Api.Blog.Controllers {
 		}
 
 		[HttpGet(nameof(Get) + "/{url}")]
-		public async Task<BlogPost> Get(string url) {
+		public async Task<ActionResult<BlogPost>> Get(string url) {
 			_logger.Log(LogLevel.Information, $"{nameof(Get)}: {nameof(url)}={url}");
 
-			if (int.TryParse(url, out int id)) {
+			try {
-				return await _blogRepository.GetPostByIdAsync(id);
+				if (int.TryParse(url, out int id)) {
-			}
+					return await _blogRepository.GetPostByIdAsync(id);
+				}
 
-			return await _blogRepository.GetPostByUrlAsync(url);
+				return await _blogRepository.GetPostByUrlAsync(url);
+			}
+			catch (ItemNotFoundException e) {
+				_logger.Log(LogLevel.Error, e.Message);
+				return NotFound("Could not find blog post");
+			}
 		}
 
 		//[HttpGet]

src/Robware.Data/BlogRepository.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Data;
 using System.Linq;
 using System.Threading.Tasks;
 using Dapper;
@@ -23,11 +24,20 @@ namespace Robware.Data
 			UserId = state.User_Id
 		};
 
+		private async Task<IEnumerable<T>> DoQuery<T>(IDbConnection connection, string query, object param = null) {
+			var result = await connection.QueryAsync<T>(query, param);
+
+			if (!result.Any())
+				throw new ItemNotFoundException(query, param);
+
+			return result;
+		}
+
 		public async Task<BlogPost> GetPostByUrlAsync(string url) {
 			const string query = "SELECT * FROM blog_posts WHERE post_url=@url AND post_deleted=0";
 			using (var connection = _dbProvider.NewConnection()) {
 				connection.Open();
-				var result = await connection.QueryAsync<BlogPostState>(query, new{url});
+				var result = await DoQuery<BlogPostState>(connection, query, new{url});
 				return MapBlogPost(result.First());
 			}
 		}
@@ -36,7 +46,7 @@ namespace Robware.Data
 			const string query = "SELECT * FROM blog_posts WHERE post_content<>'' AND post_deleted=0 ORDER BY post_timestamp DESC LIMIT @offset,@limit";
 			using (var connection = _dbProvider.NewConnection()) {
 				connection.Open();
-				var results = await connection.QueryAsync<BlogPostState>(query, new{limit, offset});
+				var results = await DoQuery<BlogPostState>(connection, query, new{limit, offset});
 				return results.Select(MapBlogPost);
 			}
 		}
@@ -48,7 +58,7 @@ namespace Robware.Data
 			var query="SELECT COUNT(*) FROM blog_posts WHERE post_content<>'' AND post_deleted=0";
 			using(var connection = _dbProvider.NewConnection()) {
 				connection.Open();
-				var result = await connection.QueryAsync<int>(query);
+				var result = await DoQuery<int>(connection, query);
 				return result.First();
 			}
 		}
@@ -57,7 +67,7 @@ namespace Robware.Data
 			const string query = "SELECT * FROM blog_posts WHERE post_id=@id AND post_deleted=0";
 			using (var connection = _dbProvider.NewConnection()) {
 				connection.Open();
-				var result = await connection.QueryAsync<BlogPostState>(query, new {id});
+				var result = await DoQuery<BlogPostState>(connection, query, new {id});
 				return MapBlogPost(result.First());
 			}
 		}
@@ -70,7 +80,7 @@ namespace Robware.Data
 
 			using (var connection = _dbProvider.NewConnection()) {
 				connection.Open();
-				var result = await connection.QueryAsync<int>(newPost ? newPostQuery : updatePostQuery, post);
+				var result = await DoQuery<int>(connection, newPost ? newPostQuery : updatePostQuery, post);
 				return newPost ? await GetPostByIdAsync(result.Single()) : post;
 			}
 		}
@@ -80,7 +90,7 @@ namespace Robware.Data
 
 			using (var connection = _dbProvider.NewConnection()) {
 				connection.Open();
-				var result = await connection.QueryAsync<BlogPostState>(query);
+				var result = await DoQuery<BlogPostState>(connection, query);
 				return result.Select(MapBlogPost);
 			}
 		}

src/Robware.Data/ItemNotFoundException.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace Robware.Data {
+	public class ItemNotFoundException:Exception {
+		public object Parameters { get; }
+
+		public ItemNotFoundException(string query, object parameters):base($"Could not find an item for the query: {query}") {
+			Parameters = parameters;
+		}
+	}
+}