Update time based strategy to use min() with < 3 data points

tests/core/utilities/test_math.py

@@ -5,6 +5,9 @@
     strategies as st,
 )
 
+from web3.exceptions import (
+    InsufficientData,
+)
 from web3.utils.math import (
     percentile,
 )
@@ -30,7 +33,7 @@ def test_percentiles_out_of_one_hundred(p, expected):
 
 
 def test_percentiles_with_single_values():
-    with pytest.raises(ValueError):
+    with pytest.raises(InsufficientData):
         percentile([0], 1)
 
 

web3/exceptions.py

@@ -99,3 +99,11 @@ class NoABIEventsFound(AttributeError):
     Raised when an ABI doesn't contain any events.
     """
     pass
+
+
+class InsufficientData(Exception):
+    """
+    Raised when there are insufficient data points to
+    complete a calculation
+    """
+    pass

web3/gas_strategies/time_based.py

@@ -7,6 +7,7 @@
 )
 
 from web3.exceptions import (
+    InsufficientData,
     ValidationError,
 )
 from web3.utils.math import (
@@ -60,11 +61,15 @@ def _aggregate_miner_data(raw_data):
 
     for miner, miner_data in data_by_miner.items():
         _, block_hashes, gas_prices = map(set, zip(*miner_data))
+        try:
+            price_percentile = percentile(gas_prices, percentile=15)
+        except InsufficientData:
+            price_percentile = min(gas_prices)
         yield MinerData(
             miner,
             len(set(block_hashes)),
             min(gas_prices),
-            percentile(gas_prices, percentile=15))
+            price_percentile)
 
 
 @to_tuple

web3/utils/math.py

@@ -1,8 +1,13 @@
+from web3.exceptions import (
+    InsufficientData,
+)
+
+
 def percentile(values=None, percentile=None):
     """Calculates a simplified weighted average percentile
     """
     if values in [None, tuple(), []] or len(values) < 3:
-        raise ValueError("Expected a sequence of at least 3 integers, got {0}".format(values))
+        raise InsufficientData("Expected a sequence of at least 3 integers, got {0}".format(values))
     if percentile is None:
         raise ValueError("Expected a percentile choice, got {0}".format(percentile))