tests/hghave.py

--- a/tests/hghave.py	Fri Jul 10 10:12:56 2020 +0200
+++ b/tests/hghave.py	Mon Jul 13 13:06:12 2020 -0400
@@ -1061,3 +1061,14 @@
     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