fix(launch): reject option-like and missing paths, resolve them absolute and drop the folder-missing page

YKanBan.Tests/Launching/LaunchArgumentsTests.cs

@@ -1,10 +1,11 @@
 using YKanBan.Launching;
+using YKanBan.Tests.TestUtilities;
 
 namespace YKanBan.Tests.Launching;
 
 /// <summary>
-/// Tests for the <c>ykanban &lt;path&gt;</c> command-line contract across its
-/// three branches: no argument, one valid path, and invalid input.
+/// Tests for the <c>ykanban &lt;path&gt;</c> command-line contract: exactly one
+/// existing folder, resolved to an absolute path; everything else is rejected.
 /// </summary>
 [TestClass]
 public class LaunchArgumentsTests {
@@ -27,9 +28,58 @@ public class LaunchArgumentsTests {
     }
 
     [TestMethod]
-    public void SinglePathIsAccepted() {
-        bool parsed = LaunchArguments.TryParse([@"C:\Repo\MyProject"], out string? path);
+    [DataRow("--help")]
+    [DataRow("-x")]
+    public void OptionLikeArgumentIsRejected(string argument) {
+        Assert.IsFalse(LaunchArguments.TryParse([argument], out string? path));
+        Assert.IsNull(path);
+    }
+
+    [TestMethod]
+    public void NonExistentFolderIsRejected() {
+        using var directory = new TempDirectory();
+        string missing = Path.Combine(directory.FullPath, "nope");
+
+        Assert.IsFalse(LaunchArguments.TryParse([missing], out string? path));
+        Assert.IsNull(path);
+    }
+
+    [TestMethod]
+    public void FileInsteadOfFolderIsRejected() {
+        using var directory = new TempDirectory();
+        string file = Path.Combine(directory.FullPath, "file.txt");
+        File.WriteAllText(file, "x");
+
+        Assert.IsFalse(LaunchArguments.TryParse([file], out string? path));
+        Assert.IsNull(path);
+    }
+
+    [TestMethod]
+    public void ExistingFolderIsAcceptedAsAnAbsolutePath() {
+        using var directory = new TempDirectory();
+
+        bool parsed = LaunchArguments.TryParse([directory.FullPath], out string? path);
+
         Assert.IsTrue(parsed);
-        Assert.AreEqual(@"C:\Repo\MyProject", path);
+        Assert.AreEqual(Path.GetFullPath(directory.FullPath), path);
+        Assert.IsTrue(Path.IsPathRooted(path));
+    }
+
+    [TestMethod]
+    public void RelativePathIsResolvedToAbsolute() {
+        using var directory = new TempDirectory();
+        string relative = Path.GetRelativePath(Environment.CurrentDirectory, directory.FullPath);
+
+        bool parsed = LaunchArguments.TryParse([relative], out string? path);
+
+        Assert.IsTrue(parsed);
+        Assert.IsTrue(Path.IsPathRooted(path));
+        Assert.AreEqual(Path.GetFullPath(relative), path);
+    }
+
+    [TestMethod]
+    public void MalformedPathIsRejected() {
+        Assert.IsFalse(LaunchArguments.TryParse(["bad\0path"], out string? path));
+        Assert.IsNull(path);
     }
 }