test: pylightning to_approx_str

contrib/pylightning/tests/test_units.py

@@ -0,0 +1,36 @@
+from lightning import Millisatoshi
+
+
+def test_to_approx_str():
+    amount = Millisatoshi('10000000sat')
+    assert amount.to_approx_str() == "0.1btc"
+    amount = Millisatoshi('1000000sat')
+    assert amount.to_approx_str() == "0.01btc"
+    amount = Millisatoshi('100000sat')
+    assert amount.to_approx_str() == "0.001btc"
+    amount = Millisatoshi('10000sat')
+    assert amount.to_approx_str() == "10000sat"
+    amount = Millisatoshi('1000sat')
+    assert amount.to_approx_str() == "1000sat"
+    amount = Millisatoshi('100msat')
+    assert amount.to_approx_str() == "0.1sat"
+
+    # also test significant rounding
+    amount = Millisatoshi('10001234sat')
+    assert amount.to_approx_str() == "0.1btc"
+    amount = Millisatoshi('1234sat')
+    assert amount.to_approx_str(3) == "1234sat"  # note: no rounding
+    amount = Millisatoshi('1234sat')
+    assert amount.to_approx_str(2) == "1234sat"  # note: no rounding
+    amount = Millisatoshi('1230sat')
+    assert amount.to_approx_str(2) == "1230sat"  # note: no rounding
+    amount = Millisatoshi('12345678sat')
+    assert amount.to_approx_str() == "0.123btc"
+    amount = Millisatoshi('12345678sat')
+    assert amount.to_approx_str(1) == "0.1btc"
+    amount = Millisatoshi('15345678sat')
+    assert amount.to_approx_str(1) == "0.2btc"
+    amount = Millisatoshi('1200000000sat')
+    assert amount.to_approx_str() == "12btc"
+    amount = Millisatoshi('1200000000sat')
+    assert amount.to_approx_str(1) == "12btc"  # note: no rounding