docs: add getting started guide for EEST opcode minilang

docs/writing_tests/writing_a_new_test.md

@@ -154,10 +154,63 @@ The code can be in either of the following formats:
 
 - `bytes` object, representing the raw opcodes in binary format.
 - `str`, representing an hexadecimal format of the opcodes.
-- `Code` compilable object.
+- `Code` compilable object (see below for supported types).
 
 `Code` objects can be concatenated together by using the `+` operator.
 
+### Using the Python Opcode Minilang (RECOMMENDED)
+
+The recommended way to write EVM bytecode for tests is to use the Python-based minilang provided by the [Opcodes][ethereum_test_vm.opcode.Opcodes] class. This allows you to construct bytecode using symbolic opcodes as Python objects.
+
+#### Example: Simple Addition Contract
+
+```python
+from ethereum_test_vm.opcode import Opcodes
+
+code = (
+    Opcodes.PUSH1(0x02)
+    + Opcodes.PUSH1(0x03)
+    + Opcodes.ADD()
+    + Opcodes.PUSH1(0x00)
+    + Opcodes.SSTORE()
+    + Opcodes.STOP()
+)
+```
+
+You can assign this `code` to the `code` field of an account in your test's `pre` or `post` state.
+
+For a full list of available opcodes and their usage, see the [Opcodes][ethereum_test_vm.opcode.Opcodes] reference.
+
+### Higher-Level Constructs
+
+For more complex control flow, you can use constructs like [Switch][ethereum_test_tools.code.generators.Switch] and [Case][ethereum_test_tools.code.generators.Case] from the [ethereum_test_tools.code.generators][ethereum_test_tools.code.generators] module:
+
+```python
+from ethereum_test_tools.code.generators import Switch, Case
+from ethereum_test_vm.opcode import Opcodes as Op
+
+code = Switch(
+    cases=[
+        Case(condition=Op.EQ(Op.CALLDATALOAD(0), 1), action=Op.PUSH1(0x01) + Op.STOP()),
+        Case(condition=Op.EQ(Op.CALLDATALOAD(0), 2), action=Op.PUSH1(0x02) + Op.STOP()),
+    ],
+    default_action=Op.PUSH1(0x00) + Op.STOP(),
+)
+```
+
+See the [ethereum_test_tools.code.generators][ethereum_test_tools.code.generators] reference for more details and additional constructs like [While][ethereum_test_tools.code.generators.While] and [Conditional][ethereum_test_tools.code.generators.Conditional].
+
+### Converting Bytecode to Minilang
+
+If you have EVM bytecode (as hex or binary), you can use the [`evm_bytes` CLI tool](../library/cli/evm_bytes.md) to convert it to the EEST Python opcode minilang automatically:
+
+- [evm_bytes CLI documentation](../library/cli/evm_bytes.md)
+- [Online reference](https://eest.ethereum.org/main/library/cli/evm_bytes/)
+
+### Restrictions: No Yul in Python Test Cases
+
+**Note:** As of [PR #1779](https://github.com/ethereum/execution-spec-tests/pull/1779), the use of Yul source in Python test cases is forbidden. All new tests must use the Python opcode minilang as shown above.
+
 ## Verifying the Accounts' Post States
 
 The state of the accounts after all blocks/transactions have been executed is