diff --git a/tests/ref/library/rgb.png b/tests/ref/library/rgb.png
deleted file mode 100644
index 37aef599f..000000000
Binary files a/tests/ref/library/rgb.png and /dev/null differ
diff --git a/tests/typ/expr/call.typ b/tests/typ/expr/call.typ
index 358322d12..0e941124c 100644
--- a/tests/typ/expr/call.typ
+++ b/tests/typ/expr/call.typ
@@ -54,7 +54,6 @@
 
 ---
 // Different forms of template arguments.
-// Ref: true
 
 #let a = "a"
 
diff --git a/tests/typ/expr/closure.typ b/tests/typ/expr/closure.typ
index d05acaa44..86a6f6328 100644
--- a/tests/typ/expr/closure.typ
+++ b/tests/typ/expr/closure.typ
@@ -1,7 +1,7 @@
 // Test closures.
+// Ref: false
 
 ---
-// Ref: false
 
 // Basic closure without captures.
 {
@@ -45,8 +45,6 @@
 }
 
 ---
-// Ref: false
-
 // Too few arguments.
 {
     let types(x, y) = "[" + type(x) + ", " + type(y) + "]"
diff --git a/tests/typ/library/box.typ b/tests/typ/library/box.typ
index eff0be3d8..10e2c93e9 100644
--- a/tests/typ/library/box.typ
+++ b/tests/typ/library/box.typ
@@ -1,3 +1,6 @@
+// Test the box function.
+
+---
 #page("a7", flip: true)
 
 // Box with fixed width, should have text height.
diff --git a/tests/typ/library/font.typ b/tests/typ/library/font.typ
index 165bdc10d..157557fed 100644
--- a/tests/typ/library/font.typ
+++ b/tests/typ/library/font.typ
@@ -1,3 +1,6 @@
+// Test the font function.
+
+---
 // Test configuring font properties.
 
 // Set same font size in three different ways.
diff --git a/tests/typ/library/hv.typ b/tests/typ/library/hv.typ
index 154445cfc..09132a60b 100644
--- a/tests/typ/library/hv.typ
+++ b/tests/typ/library/hv.typ
@@ -1,3 +1,6 @@
+// Test the h and v functions.
+
+---
 // Ends paragraphs.
 Tightly #v(-5pt) packed
 
diff --git a/tests/typ/library/image.typ b/tests/typ/library/image.typ
index 9c3cd4fe2..d3e6c78da 100644
--- a/tests/typ/library/image.typ
+++ b/tests/typ/library/image.typ
@@ -1,3 +1,6 @@
+// Test the image function.
+
+---
 // Test loading different image formats.
 
 // Load an RGBA PNG image.
diff --git a/tests/typ/library/page.typ b/tests/typ/library/page.typ
index b7ac03484..1f16f009d 100644
--- a/tests/typ/library/page.typ
+++ b/tests/typ/library/page.typ
@@ -1,3 +1,6 @@
+// Test the page function.
+
+---
 // Test configuring page sizes and margins.
 
 // Set width and height.
diff --git a/tests/typ/library/pagebreak.typ b/tests/typ/library/pagebreak.typ
index dc3e5682d..22af95126 100644
--- a/tests/typ/library/pagebreak.typ
+++ b/tests/typ/library/pagebreak.typ
@@ -1,3 +1,6 @@
+// Test the pagebreak function.
+
+---
 First of two
 #pagebreak()
 #page(height: 40pt)
diff --git a/tests/typ/library/rgb.typ b/tests/typ/library/rgb.typ
index b962bbc06..62a1627cf 100644
--- a/tests/typ/library/rgb.typ
+++ b/tests/typ/library/rgb.typ
@@ -1,17 +1,23 @@
-// Check the output.
-#rgb(0.0, 0.3, 0.7)
+// Test the rgb function.
+// Ref: false
 
-// Alpha channel.
-#rgb(1.0, 0.0, 0.0, 0.5)
+---
+{
+    // Check the output.
+    test(rgb(0.0, 0.3, 0.7), #004db3)
 
-// Warning: 2:6-2:9 should be between 0.0 and 1.0
-// Warning: 1:11-1:15 should be between 0.0 and 1.0
-#rgb(-30, 15.5, 0.5)
+    // Alpha channel.
+    test(rgb(1.0, 0.0, 0.0, 0.5), #ff000080)
 
-// Error: 6-10 missing argument: blue component
-#rgb(0, 1)
+    // Warning: 2:14-2:17 should be between 0.0 and 1.0
+    // Warning: 1:19-1:23 should be between 0.0 and 1.0
+    test(rgb(-30, 15.5, 0.5), #00ff80)
 
-// Error: 3:6-3:6 missing argument: red component
-// Error: 2:6-2:6 missing argument: green component
-// Error: 1:6-1:6 missing argument: blue component
-#rgb()
+    // Error: 14-18 missing argument: blue component
+    test(rgb(0, 1), #00ff00)
+
+    // Error: 3:14-3:14 missing argument: red component
+    // Error: 2:14-2:14 missing argument: green component
+    // Error: 1:14-1:14 missing argument: blue component
+    test(rgb(), #000000)
+}