Add trailing slash to site links within markdown

docs/example/workspace-docs/02-markdown-features.md

@@ -301,3 +301,11 @@ will be rendered as
 ```DSL
     "generatr.markdown.flexmark.extensions" "GfmTaskList"
 ```
+
+### Links to Markdown documents
+
+Placing links on markdown pages is easy. You can link to:
+
+* an overview page like [Workspace decisions](/decisions/),
+* an individual decision [ADR-0001. record architecture decisions](/decisions/1/)
+* or some system documentation like [Internet Banking](/internet-banking-system/).

src/main/kotlin/nl/avisi/structurizr/site/generatr/site/model/ToHtml.kt

@@ -14,6 +14,7 @@ import kotlinx.html.stream.createHTML
 import net.sourceforge.plantuml.FileFormat
 import net.sourceforge.plantuml.FileFormatOption
 import net.sourceforge.plantuml.SourceStringReader
+import nl.avisi.structurizr.site.generatr.site.asUrlToDirectory
 import nl.avisi.structurizr.site.generatr.site.asUrlToFile
 import nl.avisi.structurizr.site.generatr.site.views.diagram
 import org.asciidoctor.Options
@@ -134,7 +135,14 @@ private class CustomLinkResolver(private val pageViewModel: PageViewModel) : Lin
             return link
 
         return link.withStatus(LinkStatus.VALID)
-            .withUrl("/${link.url.dropWhile { it == '/' }}".asUrlToFile(pageViewModel.url))
+            .withUrl("/${link.url.dropWhile { it == '/' }}"
+                .let {
+                    if (it.endsWith('/'))
+                        it.asUrlToDirectory(pageViewModel.url)
+                    else
+                        it.asUrlToFile(pageViewModel.url)
+                }
+            )
     }
 
     class Factory(private val viewModel: PageViewModel) : LinkResolverFactory {

src/test/kotlin/nl/avisi/structurizr/site/generatr/site/model/MarkdownToHtmlTest.kt

@@ -334,4 +334,50 @@ class MarkdownToHtmlTest : ViewModelTest() {
             """.trimIndent()
         )
     }
+
+    @Test
+    fun `links to pages`() {
+        val generatorContext = generatorContext()
+        val viewModel = HomePageViewModel(generatorContext)
+
+        val html = toHtml(
+            viewModel,
+            """
+                ## header
+                Link: [Some decision](/decisions/1/),
+            """.trimIndent(),
+            Format.Markdown,
+            svgFactory
+        )
+
+        assertThat(html).isEqualTo(
+            """
+                <h2>header</h2>
+                <p>Link: <a href="decisions/1/">Some decision</a>,</p>
+            """.trimIndent()
+        )
+    }
+
+    @Test
+    fun `links to files`() {
+        val generatorContext = generatorContext()
+        val viewModel = HomePageViewModel(generatorContext)
+
+        val html = toHtml(
+            viewModel,
+            """
+                ## header
+                Link: [Some document](/document.md),
+            """.trimIndent(),
+            Format.Markdown,
+            svgFactory
+        )
+
+        assertThat(html).isEqualTo(
+            """
+                <h2>header</h2>
+                <p>Link: <a href="document.md">Some document</a>,</p>
+            """.trimIndent()
+        )
+    }
 }