diff --git a/tests/unit/security/config-file-readme.txt b/tests/unit/security/config-file-readme.txt
deleted file mode 100644
index 44e5f61..0000000
--- a/tests/unit/security/config-file-readme.txt
+++ /dev/null
@@ -1,11 +0,0 @@
-In test, we set a test-specific "HOME", which cause OS X keychain look for the
-default keychain of a "different" user. If the default keychain does not exist,
-all subsequent calls to OS X keychain will fail. User interaction (such as
-specifying password) is required to create a keychain. However, user interaction
-is not feasible in automated tests.
-
-This problem is caused by the OS X system assumption that one user must have a
-login keychain, which is also the user's default keychain, because a user
-account is always created with a login keychain as default. Thus OS X system
-infers a user according to the HOME env, and did not expect user to change the
-HOME env in normal use.
diff --git a/tests/unit/security/config-file.README.txt b/tests/unit/security/config-file.README.txt
new file mode 100644
index 0000000..f77cf65
--- /dev/null
+++ b/tests/unit/security/config-file.README.txt
@@ -0,0 +1,11 @@
+In tests, we set a test-specific HOME, which causes macOS Keychain to look for
+the default keychain of a "different" user. If the default keychain does not
+exist, all subsequent calls to macOS Keychain will fail. User interaction
+(such as entering the password) is required to create a keychain. However,
+user interaction is not feasible in automated tests.
+
+This problem is caused by macOS's assumption that a user must have a login
+keychain, which is also the user's default keychain, because a user account is
+always created with a login keychain by default. Thus, macOS infers the user
+according to the HOME env, and does not expect the user to change the HOME env
+during normal use.