Specify block number for w3.eth.estimateGas

see #1053

added feature for inputing block_identifier in eth_estimateGas command

variable inputs in estimateGas and tests

formatter for block_identifier and passing tests

added feature for inputing block_identifier in eth_estimateGas command

variable inputs in estimateGas and tests

passing lint

Author: dylanjw

tests/integration/go_ethereum/common.py

@@ -60,6 +60,14 @@ def test_eth_modifyTransaction(self, web3, unlocked_account):
         pytest.xfail('Needs ability to efficiently control mining')
         super().test_eth_modifyTransaction(web3, unlocked_account)
 
+    def test_eth_estimateGas_with_block(self,
+                                        web3,
+                                        unlocked_account_dual_type):
+        pytest.xfail('Block identifier has not been implemented in geth')
+        super().test_eth_estimateGas_with_block(
+            web3, unlocked_account_dual_type
+        )
+
 
 class GoEthereumVersionModuleTest(VersionModuleTest):
     pass

tests/integration/test_ethereum_tester.py

@@ -280,6 +280,14 @@ def test_eth_getStorageAt(self, web3, emitter_contract_address):
         pytest.xfail('json-rpc method is not implemented on eth-tester')
         super().test_eth_getStorageAt(web3, emitter_contract_address)
 
+    def test_eth_estimateGas_with_block(self,
+                                        web3,
+                                        unlocked_account_dual_type):
+        pytest.xfail('Block identifier has not been implemented in eth-tester')
+        super().test_eth_estimateGas_with_block(
+            web3, unlocked_account_dual_type
+        )
+
 
 class TestEthereumTesterVersionModule(VersionModuleTest):
     pass

web3/_utils/abi.py

@@ -356,6 +356,11 @@ def is_string_type(abi_type):
     return abi_type == 'string'
 
 
+@curry
+def is_length(target_length, value):
+    return len(value) == target_length
+
+
 def size_of_type(abi_type):
     """
     Returns size in bits of abi_type

web3/_utils/module_testing/eth_module.py

@@ -469,6 +469,17 @@ def test_eth_estimateGas(self, web3, unlocked_account_dual_type):
         assert is_integer(gas_estimate)
         assert gas_estimate > 0
 
+    def test_eth_estimateGas_with_block(self,
+                                        web3,
+                                        unlocked_account_dual_type):
+        gas_estimate = web3.eth.estimateGas({
+            'from': unlocked_account_dual_type,
+            'to': unlocked_account_dual_type,
+            'value': 1,
+        }, 'latest')
+        assert is_integer(gas_estimate)
+        assert gas_estimate > 0
+
     def test_eth_getBlockByHash(self, web3, empty_block):
         block = web3.eth.getBlock(empty_block['hash'])
         assert block['hash'] == empty_block['hash']

web3/eth.py

@@ -294,15 +294,22 @@ def call(self, transaction, block_identifier=None):
             [transaction, block_identifier],
         )
 
-    def estimateGas(self, transaction):
+    def estimateGas(self, transaction, block_identifier=None):
         # TODO: move to middleware
         if 'from' not in transaction and is_checksum_address(self.defaultAccount):
             transaction = assoc(transaction, 'from', self.defaultAccount)
 
-        return self.web3.manager.request_blocking(
-            "eth_estimateGas",
-            [transaction],
-        )
+        # TODO: move to middleware
+        if block_identifier is None:
+            return self.web3.manager.request_blocking(
+                "eth_estimateGas",
+                [transaction],
+            )
+        else:
+            return self.web3.manager.request_blocking(
+                "eth_estimateGas",
+                [transaction, block_identifier],
+            )
 
     def filter(self, filter_params=None, filter_id=None):
         if filter_id and filter_params:

web3/middleware/pythonic.py

@@ -16,6 +16,9 @@
     HexBytes,
 )
 
+from web3._utils.abi import (
+    is_length,
+)
 from web3._utils.encoding import (
     hexstr_if_str,
     to_hex,
@@ -244,6 +247,12 @@ def to_hexbytes(num_bytes, val, variable_length=False):
     apply_formatters_to_dict(TRANSACTION_PARAM_FORMATTERS),
 )
 
+estimate_gas_without_block_id = apply_formatter_at_index(transaction_param_formatter, 0)
+estimate_gas_with_block_id = combine_argument_formatters(
+    transaction_param_formatter,
+    block_number_formatter,
+)
+
 
 pythonic_middleware = construct_formatting_middleware(
     request_formatters={
@@ -273,7 +282,10 @@ def to_hexbytes(num_bytes, val, variable_length=False):
             transaction_param_formatter,
             block_number_formatter,
         ),
-        'eth_estimateGas': apply_formatter_at_index(transaction_param_formatter, 0),
+        'eth_estimateGas': apply_one_of_formatters((
+            (estimate_gas_without_block_id, is_length(1)),
+            (estimate_gas_with_block_id, is_length(2)),
+        )),
         'eth_sendTransaction': apply_formatter_at_index(transaction_param_formatter, 0),
         # personal
         'personal_importRawKey': apply_formatter_at_index(