From 43d2e8feeaa4c3e75a33b8d1e0c6e4bafda5d944 Mon Sep 17 00:00:00 2001
From: Oliver Booth <me@olivr.me>
Date: Sun, 27 Aug 2023 13:19:42 +0100
Subject: [PATCH] test: add tests for MDLink

---
 X10D.Tests/src/Text/MarkdownTests.cs | 40 ++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/X10D.Tests/src/Text/MarkdownTests.cs b/X10D.Tests/src/Text/MarkdownTests.cs
index 46a70ad..28bc5eb 100644
--- a/X10D.Tests/src/Text/MarkdownTests.cs
+++ b/X10D.Tests/src/Text/MarkdownTests.cs
@@ -105,6 +105,46 @@ internal class MarkdownTests
         Assert.That("Hello, world!".MDItalic(true), Is.EqualTo("_Hello, world!_"));
     }
 
+    [Test]
+    public void MDLink_ShouldThrowArgumentNullException_GivenNullUrl()
+    {
+        Assert.Multiple(() =>
+        {
+            Assert.Throws<ArgumentNullException>(() => "".MDLink((string)null!));
+            Assert.Throws<ArgumentNullException>(() => "".MDLink((Uri)null!));
+            Assert.Throws<ArgumentNullException>(() => ((Uri)null!).MDLink("Hello, world!"));
+        });
+    }
+
+    [Test]
+    public void MDLink_ShouldReturnUrlOnly_GivenNullOrEmptyLabel()
+    {
+        const string url = "https://example.com/";
+        Assert.Multiple(() =>
+        {
+            Assert.That(((string)null!).MDLink(url), Is.EqualTo(url));
+            Assert.That(string.Empty.MDLink(url), Is.EqualTo(url));
+
+            Assert.That(new Uri(url).MDLink(null), Is.EqualTo(url));
+            Assert.That(new Uri(url).MDLink(string.Empty), Is.EqualTo(url));
+        });
+    }
+
+    [Test]
+    public void MDLink_ShouldReturnFormattedLink_GivenValidLabelAndUrl()
+    {
+        const string url = "https://example.com/";
+        const string label = "Hello, world!";
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(label.MDLink(url), Is.EqualTo($"[{label}]({url})"));
+            Assert.That(label.MDLink(new Uri(url)), Is.EqualTo($"[{label}]({url})"));
+
+            Assert.That(new Uri(url).MDLink(label), Is.EqualTo($"[{label}]({url})"));
+        });
+    }
+
     [Test]
     public void MDStrikeOut_ShouldThrowArgumentNullException_GivenNull()
     {