diff --git a/test/LibplanetConsole.Console.Tests/ConsoleApplicationSource.cs b/test/LibplanetConsole.Console.Tests/ConsoleApplicationSource.cs
index a3d2c4b1..50592fda 100644
--- a/test/LibplanetConsole.Console.Tests/ConsoleApplicationSource.cs
+++ b/test/LibplanetConsole.Console.Tests/ConsoleApplicationSource.cs
@@ -8,11 +8,16 @@ public static void Main(string[] args)
     {
         var delay = args.Length > 0 ? int.Parse(args[0]) : 1000;
         var dateTimeOffset = DateTimeOffset.UtcNow;
-        while (DateTimeOffset.UtcNow < dateTimeOffset.AddMilliseconds(delay))
+        var endDateTimeOffset = dateTimeOffset.AddMilliseconds(delay);
+        while ((dateTimeOffset = DateTimeOffset.UtcNow) < endDateTimeOffset)
         {
             System.Threading.Thread.Sleep(100);
+            System.Console.Out.Write("out: ");
             System.Console.Out.WriteLine(dateTimeOffset);
+            System.Console.Error.Write("error: ");
             System.Console.Error.WriteLine(dateTimeOffset);
         }
+
+        System.Console.Out.Write(dateTimeOffset.ToString("o"));
     }
 }
diff --git a/test/LibplanetConsole.Console.Tests/ProcessTest.cs b/test/LibplanetConsole.Console.Tests/ProcessTest.cs
index 19c4e2b1..695f27b9 100644
--- a/test/LibplanetConsole.Console.Tests/ProcessTest.cs
+++ b/test/LibplanetConsole.Console.Tests/ProcessTest.cs
@@ -1,3 +1,4 @@
+using System.Globalization;
 using Xunit.Extensions.AssemblyFixture;
 
 namespace LibplanetConsole.Console.Tests;
@@ -94,7 +95,9 @@ public void Run_DotnetHelp_Test()
     {
         var dotnetPath = ProcessEnvironment.DotnetPath;
         var process = new TestProcess(dotnetPath, "--help");
+        using var outputCollector = new ProcessOutputCollector(process);
         process.Run();
+        Assert.NotEmpty(outputCollector.Output);
         Assert.False(process.IsRunning);
         Assert.Equal(-1, process.Id);
     }
@@ -104,7 +107,9 @@ public async Task RunAsync_DotnetHelp_TestAsync()
     {
         var dotnetPath = ProcessEnvironment.DotnetPath;
         var process = new TestProcess(dotnetPath, "--help");
+        using var outputCollector = new ProcessOutputCollector(process);
         await process.RunAsync(default);
+        Assert.NotEmpty(outputCollector.Output);
         Assert.False(process.IsRunning);
         Assert.Equal(-1, process.Id);
     }
@@ -114,12 +119,18 @@ public void Run_DotnetHelp_Twice_Test()
     {
         var dotnetPath = ProcessEnvironment.DotnetPath;
         var process = new TestProcess(dotnetPath, "--help");
+        var outputCollector1 = new ProcessOutputCollector(process);
         process.Run();
+        outputCollector1.Dispose();
         Assert.False(process.IsRunning);
         Assert.Equal(-1, process.Id);
+        var outputCollector2 = new ProcessOutputCollector(process);
         process.Run();
+        outputCollector2.Dispose();
         Assert.False(process.IsRunning);
         Assert.Equal(-1, process.Id);
+
+        Assert.Equal(outputCollector1.Output, outputCollector2.Output);
     }
 
     [Fact]
@@ -127,12 +138,18 @@ public async Task RunAsync_DotnetHelp_Twice_TestAsync()
     {
         var dotnetPath = ProcessEnvironment.DotnetPath;
         var process = new TestProcess(dotnetPath, "--help");
+        var outputCollector1 = new ProcessOutputCollector(process);
         await process.RunAsync(default);
+        outputCollector1.Dispose();
         Assert.False(process.IsRunning);
         Assert.Equal(-1, process.Id);
+        var outputCollector2 = new ProcessOutputCollector(process);
         await process.RunAsync(default);
+        outputCollector2.Dispose();
         Assert.False(process.IsRunning);
         Assert.Equal(-1, process.Id);
+
+        Assert.Equal(outputCollector1.Output, outputCollector2.Output);
     }
 
     [Fact]
@@ -141,7 +158,14 @@ public void Run_Runtime_Test()
         var dotnetPath = ProcessEnvironment.DotnetPath;
         var executionPath = consoleApplicationFixture.ExecutionPath;
         var process = new TestProcess(dotnetPath, executionPath);
+        using var outputCollector = new ProcessOutputCollector(process);
+        var expectedTimestamp = DateTimeOffset.UtcNow + TimeSpan.FromMilliseconds(1000);
         process.Run();
+        var output = outputCollector.Output;
+        var lines = output.Split(new[] { Environment.NewLine }, StringSplitOptions.None);
+        var actualTimestamp = DateTimeOffset.Parse(lines.Last(), CultureInfo.CurrentCulture);
+
+        Assert.True(actualTimestamp >= expectedTimestamp);
         Assert.False(process.IsRunning);
         Assert.Equal(-1, process.Id);
     }
@@ -152,7 +176,14 @@ public async Task RunAsync_Runtime_TestAsync()
         var dotnetPath = ProcessEnvironment.DotnetPath;
         var executionPath = consoleApplicationFixture.ExecutionPath;
         var process = new TestProcess(dotnetPath, executionPath);
+        using var outputCollector = new ProcessOutputCollector(process);
+        var expectedTimestamp = DateTimeOffset.UtcNow + TimeSpan.FromMilliseconds(1000);
         await process.RunAsync(default);
+        var output = outputCollector.Output;
+        var lines = output.Split(new[] { Environment.NewLine }, StringSplitOptions.None);
+        var actualTimestamp = DateTimeOffset.Parse(lines.Last(), CultureInfo.CurrentCulture);
+
+        Assert.True(actualTimestamp >= expectedTimestamp);
         Assert.False(process.IsRunning);
         Assert.Equal(-1, process.Id);
     }
@@ -213,11 +244,21 @@ public async Task RunAsync_TestId_TestAsync()
     {
         var dotnetPath = ProcessEnvironment.DotnetPath;
         var executionPath = consoleApplicationFixture.ExecutionPath;
-        var process = new TestProcess(dotnetPath, executionPath, "1000");
+        var millisecondsDelay = Random.Shared.Next(1000, 2000);
+        var process = new TestProcess(dotnetPath, executionPath, $"{millisecondsDelay}");
+        using var outputCollector = new ProcessOutputCollector(process);
+        var expectedTimestamp
+            = DateTimeOffset.UtcNow + TimeSpan.FromMilliseconds(millisecondsDelay);
         var task = process.RunAsync(default);
+
         Assert.True(process.IsRunning);
         Assert.NotEqual(-1, process.Id);
         await task;
+
+        var output = outputCollector.Output;
+        var lines = output.Split(new[] { Environment.NewLine }, StringSplitOptions.None);
+        var actualTimestamp = DateTimeOffset.Parse(lines.Last(), CultureInfo.CurrentCulture);
+        Assert.True(actualTimestamp >= expectedTimestamp);
         Assert.False(process.IsRunning);
         Assert.Equal(-1, process.Id);
     }