fix(cli): resolve CLI-002..007 — robust response rendering, URL/JSON arg validation, credential env-vars, doc refresh

tests/ScadaLink.CLI.Tests/UrlValidationTests.cs

@@ -0,0 +1,31 @@
+using ScadaLink.CLI.Commands;
+
+namespace ScadaLink.CLI.Tests;
+
+/// <summary>
+/// Regression tests for CLI-004 — a malformed <c>--url</c> previously reached
+/// <c>new Uri(...)</c> in the <see cref="ScadaLink.CLI.ManagementHttpClient"/> constructor
+/// and threw an unhandled <see cref="UriFormatException"/>.
+/// </summary>
+public class UrlValidationTests
+{
+    [Theory]
+    [InlineData("http://localhost:9001")]
+    [InlineData("https://central-host:5000/")]
+    [InlineData("http://central")]
+    public void IsValidManagementUrl_AcceptsAbsoluteHttpUrls(string url)
+    {
+        Assert.True(CommandHelpers.IsValidManagementUrl(url));
+    }
+
+    [Theory]
+    [InlineData("localhost:9001")]   // no scheme
+    [InlineData("")]                  // empty
+    [InlineData("   ")]               // whitespace
+    [InlineData("not a url")]
+    [InlineData("ftp://central:21")]  // non-http scheme
+    public void IsValidManagementUrl_RejectsMalformedOrNonHttpUrls(string url)
+    {
+        Assert.False(CommandHelpers.IsValidManagementUrl(url));
+    }
+}