diff -r 40120de810ba -r 2c0043977b6d tests/hghave.py
--- a/tests/hghave.py	Wed Jul 08 08:25:30 2020 +0200
+++ b/tests/hghave.py	Wed Jul 08 08:57:21 2020 +0200
@@ -1074,3 +1074,14 @@
     return matchoutput(
         '`rustup which --toolchain nightly rustfmt` --version', b'rustfmt'
     )
+
+
+@check("lzma", "python lzma module")
+def has_lzma():
+    try:
+        import _lzma
+
+        _lzma.FORMAT_XZ
+        return True
+    except ImportError:
+        return False