diff --git a/tests/locale.in b/tests/checks/locale.fish
similarity index 75%
rename from tests/locale.in
rename to tests/checks/locale.fish
index ccdd87439..b0e7a73e8 100644
--- a/tests/locale.in
+++ b/tests/checks/locale.fish
@@ -1,7 +1,18 @@
-# Test behavior related to the locale.
+#RUN: %fish %s
+# A function to display bytes, necessary because GNU and BSD implementations of `od` have different output.
+# We used to use xxd, but it's not available everywhere. See #3797.
+#
+# We use the lowest common denominator format, `-b`, because it should work in all implementations.
+# I wish we could use the `-t` flag but it isn't available in every OS we're likely to run on.
+#
+function display_bytes
+    od -b | sed -e 's/  */ /g' -e 's/  *$//'
+end
 
 # Verify that our UTF-8 locale produces the expected output.
 echo -n A\u00FCA | display_bytes
+#CHECK: 0000000 101 303 274 101
+#CHECK: 0000004
 
 # Verify that exporting a change to the C locale produces the expected output.
 # The output should include the literal byte \xFC rather than the UTF-8 sequence for \u00FC.
@@ -9,10 +20,14 @@ begin
 	set -lx LC_ALL C
 	echo -n B\u00FCB | display_bytes
 end
+#CHECK: 0000000 102 374 102
+#CHECK: 0000003
 
 # Since the previous change was localized to a block it should no
 # longer be in effect and we should be back to a UTF-8 locale.
 echo -n C\u00FCC | display_bytes
+#CHECK: 0000000 103 303 274 103
+#CHECK: 0000004
 
 # Verify that setting a non-exported locale var doesn't affect the behavior.
 # The output should include the UTF-8 sequence for \u00FC rather than that literal byte.
@@ -21,6 +36,8 @@ begin
 	set -l LC_ALL C
 	echo -n D\u00FCD | display_bytes
 end
+#CHECK: 0000000 104 303 274 104
+#CHECK: 0000004
 
 # Verify that fish can pass through non-ASCII characters in the C/POSIX
 # locale. This is to prevent regression of
@@ -40,6 +57,10 @@ end
 # second.
 echo -n X\u00FBX | display_bytes
 echo X\u00FCX | env LC_ALL=C ../test/root/bin/fish -c 'read foo; echo -n $foo' | display_bytes
+#CHECK: 0000000 130 303 273 130
+#CHECK: 0000004
+#CHECK: 0000000 130 303 274 130
+#CHECK: 0000004
 
 # The next tests deliberately spawn another fish instance to test inheritance of env vars.
 
@@ -50,8 +71,12 @@ echo X\u00FCX | env LC_ALL=C ../test/root/bin/fish -c 'read foo; echo -n $foo' |
 # ISO 8859-x char sets which are encompassed by the C locale. The output should
 # be "59fc59".
 env LC_ALL=C ../test/root/bin/fish -c 'echo -n Y\u00FCY' | display_bytes
+#CHECK: 0000000 131 374 131
+#CHECK: 0000003
 
 # The user can specify a wide unicode character (one requiring more than a
 # single byte). In the C/POSIX locales we substitute a question-mark for the
 # unencodable wide char. The output should be "543f54".
 env LC_ALL=C ../test/root/bin/fish -c 'echo -n T\u01FDT' | display_bytes
+#CHECK: 0000000 124 077 124
+#CHECK: 0000003
diff --git a/tests/locale.err b/tests/locale.err
deleted file mode 100644
index e69de29bb..000000000
diff --git a/tests/locale.out b/tests/locale.out
deleted file mode 100644
index 9aa8faf19..000000000
--- a/tests/locale.out
+++ /dev/null
@@ -1,16 +0,0 @@
-0000000 101 303 274 101
-0000004
-0000000 102 374 102
-0000003
-0000000 103 303 274 103
-0000004
-0000000 104 303 274 104
-0000004
-0000000 130 303 273 130
-0000004
-0000000 130 303 274 130
-0000004
-0000000 131 374 131
-0000003
-0000000 124 077 124
-0000003