From 478dfd74fc4b22512a33b9a77e9a2df5b7805707 Mon Sep 17 00:00:00 2001
From: Martin von Zweigbergk <martinvonz@google.com>
Date: Sun, 28 Aug 2022 21:07:51 -0700
Subject: [PATCH] tests: teach fake editor to check that initial text is as
 expected

---
 testing/fake-editor.rs         | 7 +++++++
 tests/test_describe_command.rs | 7 +++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/testing/fake-editor.rs b/testing/fake-editor.rs
index 161af108c..937d61c5f 100644
--- a/testing/fake-editor.rs
+++ b/testing/fake-editor.rs
@@ -37,6 +37,13 @@ fn main() {
         match parts.as_slice() {
             [""] => {}
             ["fail"] => exit(1),
+            ["expect"] => {
+                let actual = String::from_utf8(std::fs::read(&args.file).unwrap()).unwrap();
+                if actual != payload {
+                    eprintln!("unexpected content: {}", actual);
+                    exit(1)
+                }
+            }
             ["write"] => {
                 std::fs::write(&args.file, payload).unwrap();
             }
diff --git a/tests/test_describe_command.rs b/tests/test_describe_command.rs
index 782a00e56..5928f7c16 100644
--- a/tests/test_describe_command.rs
+++ b/tests/test_describe_command.rs
@@ -30,8 +30,11 @@ fn test_describe() {
     Working copy now at: 7e0db3b0ad17 description from CLI
     "###);
 
-    // Test making no changes
-    std::fs::write(&edit_script, "").unwrap();
+    // Check that the text file gets initialized with the current description and make no changes
+    std::fs::write(&edit_script, r#"expect
+description from CLI
+JJ: Lines starting with "JJ: " (like this one) will be removed.
+"#).unwrap();
     let stdout = test_env.jj_cmd_success(&repo_path, &["describe"]);
     insta::assert_snapshot!(stdout, @r###"
     Working copy now at: 45bfa10db64d description from CLI