pyln: failing test msat from float str

[m-schmoock]

Currently we are not able to create pyln Millisatoshi from floats, e.g.:

• "0.01btc"
• "0.1sat"
• ...

This adds a test that is currently expected to fail because of this bug.

Changelog-None

[rustyrussell]

Hmm, how's this?

diff --git a/contrib/pyln-client/pyln/client/lightning.py b/contrib/pyln-client/pyln/client/lightning.py
index 4a7ee33f0..c970edaac 100644
--- a/contrib/pyln-client/pyln/client/lightning.py
+++ b/contrib/pyln-client/pyln/client/lightning.py
@@ -49,11 +49,11 @@ class Millisatoshi:
         """
         if isinstance(v, str):
             if v.endswith("msat"):
-                self.millisatoshis = int(v[0:-4])
+                self.millisatoshis = Decimal(v[0:-4])
             elif v.endswith("sat"):
-                self.millisatoshis = int(v[0:-3]) * 1000
+                self.millisatoshis = Decimal(v[0:-3]) * 1000
             elif v.endswith("btc"):
-                self.millisatoshis = int(v[0:-3]) * 1000 * 10**8
+                self.millisatoshis = Decimal(v[0:-3]) * 1000 * 10**8
             else:
                 raise TypeError(
                     "Millisatoshi must be string with msat/sat/btc suffix or"

(untested!)

[m-schmoock]

@rustyrussell I took your suggestion except setting the Decimal to an intermediate variable, which was necessary so we do not get flake8 nits: error: Incompatible types in assignment (expression has type "int", variable has type "Decimal")

I also extended the testcase a bit

[rustyrussell]

Ack a32a686

Thanks!