[spec] Add Behave (cucumber) specifications to python

Makefile

@@ -8,14 +8,17 @@ test-coverage:
 	poetry run python -m coverage run -m unittest discover -s aptos_sdk/ -p '*.py' -t ..
 	poetry run python -m coverage report
 
+test-spec:
+	poetry run behave
+
 fmt:
-	find ./examples ./aptos_sdk . -type f -name "*.py" | xargs poetry run autoflake -i -r --remove-all-unused-imports --remove-unused-variables --ignore-init-module-imports
-	poetry run isort aptos_sdk examples
-	poetry run black aptos_sdk examples
+	find ./examples ./aptos_sdk ./features . -type f -name "*.py" | xargs poetry run autoflake -i -r --remove-all-unused-imports --remove-unused-variables --ignore-init-module-imports
+	poetry run isort aptos_sdk examples features
+	poetry run black aptos_sdk examples features
 
 lint:
-	poetry run mypy aptos_sdk examples
-	poetry run flake8 aptos_sdk examples
+	poetry run mypy aptos_sdk examples features
+	poetry run flake8 aptos_sdk examples features
 
 examples:
 	poetry run python -m examples.aptos_token

features/account_address.feature

@@ -0,0 +1,68 @@
+Feature: Account Address
+"""
+AccountAddress is a 32-byte value that represents an address on chain.
+"""
+
+  Scenario Outline: Parse account address <label>
+    Given string <str>
+    When I parse the account address
+    Then the result should be address <address>
+    Examples:
+      | label                     | str                                          | address                                    |
+      | address one short         | "0x1"                                        | 0x1                                        |
+      | address one long          | "0x0000000000000000000000000000000000000001" | 0x1                                        |
+      | address two short         | "0x2"                                        | 0x2                                        |
+      | address two long          | "0x0000000000000000000000000000000000000002" | 0x2                                        |
+      | full address              | "0x1111111111111111111111111111111111111112" | 0x1111111111111111111111111111111111111112 |
+      | address with leading 0    | "0x0111111111111111111111111111111111111112" | 0x0111111111111111111111111111111111111112 |
+      | address missing leading 0 | "0x111111111111111111111111111111111111112"  | 0x111111111111111111111111111111111111112  |
+
+  Scenario Outline: Address <label> to string
+  """
+  TODO: AIP-40 doesn't shorten 0xB
+  TODO: Uppercase or lowercase?
+  """
+    Given address <address>
+    When I convert the address to a string
+    Then the result should be string <str>
+
+    Examples:
+      | label                  | str                                                                  | address                                                            |
+      | address one            | "0x1"                                                                | 0x1                                                                |
+      | address two            | "0x2"                                                                | 0x2                                                                |
+      | address two long       | "0x2"                                                                | 0x0000000000000000000000000000000000000002                         |
+      | address A              | "0xa"                                                                | 0xA                                                                |
+      | address B              | "0xb"                                                                | 0xB                                                                |
+      | full address           | "0x0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef" | 0x0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef |
+      | address with leading 0 | "0x0000000000000000000000000111111111111111111111111111111111111112" | 0x0111111111111111111111111111111111111112                         |
+
+  Scenario Outline: Address <label> to string long
+  """
+  This is required for indexer support
+  """
+    Given address <address>
+    When I convert the address to a string long
+    Then the result should be string <str>
+
+    Examples:
+      | label                     | str                                                                  | address                                                            |
+      | address one               | "0x0000000000000000000000000000000000000000000000000000000000000001" | 0x1                                                                |
+      | address two               | "0x0000000000000000000000000000000000000000000000000000000000000002" | 0x2                                                                |
+      | address A                 | "0x000000000000000000000000000000000000000000000000000000000000000a" | 0xA                                                                |
+      | address B                 | "0x000000000000000000000000000000000000000000000000000000000000000b" | 0xB                                                                |
+      | full address              | "0x0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef" | 0x0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef |
+      | address with leading 0    | "0x0000000000000000000000000111111111111111111111111111111111111112" | 0x0111111111111111111111111111111111111112                         |
+      | address missing leading 0 | "0x0000000000000000000000000111111111111111111111111111111111111112" | 0x111111111111111111111111111111111111112                          |
+
+
+  Scenario Outline: Parse account address with invalid address <label>
+    Given string "<address>"
+    When I parse the account address
+    Then I should fail to parse the account address
+    Examples:
+      | label                       | address                                                             |
+      | address no digits           | 0x                                                                  |
+      | address too long            | 0xA0000000000000000000000000000000000000000000000000000000000000001 |
+      | address too long with zeros | 0x00000000000000000000000000000000000000000000000000000000000000001 |
+      | address invalid character   | 0xG                                                                 |
+