feat: As a user, I want to have an example schema checker module

contracts/src/examples/modules/SchemaCheckerModule.sol

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.21;
+
+import { AbstractModule } from "../../interface/AbstractModule.sol";
+import { AttestationPayload } from "../../types/Structs.sol";
+
+/**
+ * @title Schema checker Module
+ * @notice This contract illustrates a valid Module that is used to check the schema that an attestation is based on
+ */
+contract SchemaCheckerModule is AbstractModule {
+  error InvalidSchemaId();
+  /*
+   * @notice This is an example of how to check the attestation payload encoding/decoding, based on a "Profile Schema"
+   */
+  struct Profile {
+    address issuer;
+    bytes32 schemaId;
+    uint64 issueDate;
+  }
+
+  /**
+   * @inheritdoc AbstractModule
+   * @notice This method is used to run the module's validation logic
+   * @param attestationPayload - AttestationPayload containing the user address as `subject` and nonce as `attestationData`
+   */
+  function run(
+    AttestationPayload memory attestationPayload,
+    bytes memory /*validationPayload*/,
+    address /*txSender*/,
+    uint256 /*value*/
+  ) public view override {
+    if (keccak256(abi.encodePacked(attestationPayload.schemaId)) != keccak256(abi.encode(bytes32("12345678")))) {
+      revert InvalidSchemaId();
+    }
+    abi.decode(attestationPayload.attestationData, (address, bytes32, uint64));
+  }
+}

contracts/test/example/SchemaCheckerModule.t.sol

@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.21;
+
+import { Test } from "forge-std/Test.sol";
+import { AbstractModule } from "../../src/interface/AbstractModule.sol";
+import { SchemaCheckerModule } from "../../src/examples/modules/SchemaCheckerModule.sol";
+import { AttestationPayload } from "../../src/types/Structs.sol";
+
+contract SchemaCheckerModuleTest is Test {
+  SchemaCheckerModule private schemaCheckerModule;
+  address internal issuer;
+
+  event ModuleRegistered(string name, string description, address moduleAddress);
+
+  function setUp() public {
+    issuer = makeAddr("issuer");
+    schemaCheckerModule = new SchemaCheckerModule();
+    vm.deal(issuer, 1 ether);
+  }
+
+  function test_SchemaCheckerModule_matchSchemaId() public {
+    address user = makeAddr("user");
+    uint64 issueDate = 0;
+    AttestationPayload memory attestationPayload = AttestationPayload(
+      bytes32("12345678"),
+      0,
+      abi.encode(user),
+      abi.encode(issuer, "112334", issueDate)
+    );
+
+    schemaCheckerModule.run(attestationPayload, bytes("0000"), user, 0);
+  }
+
+  function test_SchemaCheckerModule_InvalidSchemaId() public {
+    address user = makeAddr("user");
+    bytes32 schemaId = bytes32(uint256(1234));
+    uint64 issueDate = 0;
+    AttestationPayload memory attestationPayload = AttestationPayload(
+      schemaId,
+      0,
+      abi.encode(user),
+      abi.encode(issuer, bytes32(uint256(4321)), issueDate)
+    );
+
+    vm.expectRevert(SchemaCheckerModule.InvalidSchemaId.selector);
+    schemaCheckerModule.run(attestationPayload, bytes("0000"), user, 0);
+  }
+
+  function test_SchemaCheckerModule_supportsInterface() public {
+    bool isAbstractModuleSupported = schemaCheckerModule.supportsInterface(type(AbstractModule).interfaceId);
+    assertEq(isAbstractModuleSupported, true);
+  }
+}