Add FileArgument tests, update readme

Author: sleeuwen

README.md

@@ -22,6 +22,7 @@ Options:
 Commands:
   merge <file> <files>        merge two or more json files into one
   set <file> <key> <value>    set a value in a json file
+  remove <file> <key>         Remove a value from the json
 ```
 
 ### Commands
@@ -38,11 +39,11 @@ Usage:
   dotnet-json merge [options] <file> <files>...
 
 Arguments:
-  <file>     The name of the first file (use '-' to read from STDIN)
+  <file>     The JSON file (use '-' for STDIN)
   <files>    The names of the files to merge with the first file.
 
 Options:
-  -o, --output <file>    The filename to write the merge result into, leave out to write back into the first file (use '-' to write to STDOUT).
+  -o, --output <file>    The output file (use '-' for STDOUT, defaults to <file>)
   -?, -h, --help         Show help and usage information
 ```
 
@@ -58,10 +59,31 @@ Usage:
   dotnet-json set [options] <file> <key> <value>
 
 Arguments:
-  <file>     The JSON file (use '-' to read from STDIN and write to STDOUT)
+  <file>     The JSON file (use '-' for STDIN)
   <key>      The key to set (use ':' to set nested object and use index numbers to set array values eg. nested:key or nested:1:key)
   <value>    The value to set
 
 Options:
-  -?, -h, --help    Show help and usage information
+  -o, --output <file>    The output file (use '-' for STDOUT, defaults to <file>)
+  -?, -h, --help         Show help and usage information
+```
+
+#### remove
+
+Updates the json file to remove a key from the file. Use `:` as separator for nested objects.
+
+```
+remove:
+  Remove a value from the json
+
+Usage:
+  dotnet-json remove [options] <file> <key>
+
+Arguments:
+  <file>    The JSON file (use '-' for STDIN)
+  <key>     The JSON key to remove
+
+Options:
+  -o, --output <file>    The output file (use '-' for STDOUT, defaults to <file>)
+  -?, -h, --help         Show help and usage information
 ```

dotnet-json.Tests/FileArgumentTests.cs

@@ -0,0 +1,76 @@
+using System;
+using System.CommandLine;
+using System.CommandLine.Invocation;
+using System.CommandLine.IO;
+using System.IO;
+using System.Threading.Tasks;
+using dotnet_json.Commands;
+using FluentAssertions;
+using Xunit;
+
+namespace dotnet_json.Tests
+{
+    public class FileArgumentTests
+    {
+        [Fact]
+        public async Task SucceedsWhenFileExists()
+        {
+            var tmpDir = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName());
+            Directory.CreateDirectory(tmpDir);
+
+            try
+            {
+                var filename = Path.Combine(tmpDir, "file.json");
+                await File.WriteAllTextAsync(Path.Combine(tmpDir, filename), "{}");
+
+                var (exitCode, console) = await RunCommand(filename);
+
+                exitCode.Should().Be(0);
+                console.Error.ToString().Should().BeEmpty();
+                console.Out.ToString().Should().Contain($"Success {filename}");
+            }
+            finally
+            {
+                Directory.Delete(tmpDir, true);
+            }
+        }
+
+        [Fact]
+        public async Task SucceedsWithStandardInputOutput()
+        {
+            var (exitCode, console) = await RunCommand("-");
+
+            exitCode.Should().Be(0);
+            console.Error.ToString().Should().BeEmpty();
+            console.Out.ToString().Should().Contain("Success -");
+        }
+
+        [Fact]
+        public async Task ThrowsWhenFileDoesNotExist()
+        {
+            var (exitCode, console) = await RunCommand("this-file-does-not-exist.json");
+
+            exitCode.Should().NotBe(0);
+            console.Error.ToString().Should().Contain("File does not exist: this-file-does-not-exist.json");
+        }
+
+        private async Task<(int ExitCode, IConsole Console)> RunCommand(string filename)
+        {
+            var file = new FileArgument("file");
+
+            var command = new RootCommand();
+            command.AddArgument(file);
+
+            var console = new TestConsole();
+
+            command.Handler = CommandHandler.Create((string file) =>
+            {
+                console.Out.Write("Success " + file);
+                return 0;
+            });
+
+            var exitCode = await command.InvokeAsync(filename, console);
+            return (exitCode, console);
+        }
+    }
+}

dotnet-json/Commands/MergeCommand.cs

@@ -42,7 +42,7 @@ protected override async Task<int> ExecuteAsync()
             return 0;
         }
 
-        private Stream GetStream(string filename) => filename switch
+        private static Stream GetStream(string filename) => filename switch
         {
             "-" => Console.OpenStandardInput(),
             _ => File.OpenRead(filename),