From 938d601fbc9fa0a13f6f84753f60d61117d9a448 Mon Sep 17 00:00:00 2001
From: Gavin Nishizawa <gavin@terrastruct.com>
Date: Fri, 22 Sep 2023 14:52:16 -0700
Subject: [PATCH] add format test

---
 d2format/format_test.go | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/d2format/format_test.go b/d2format/format_test.go
index 889b01537..c6dd79296 100644
--- a/d2format/format_test.go
+++ b/d2format/format_test.go
@@ -810,6 +810,25 @@ steps: {
     step-1-content
   }
 }
+`,
+		},
+		{
+			name: "substitution_mid_string",
+			in: `vars: {
+  test: hello
+}
+
+mybox: {
+  label: prefix${test}suffix
+}
+`,
+			exp: `vars: {
+  test: hello
+}
+
+mybox: {
+  label: prefix${test}suffix
+}
 `,
 		},
 	}