feat: add prometheus basic unit test

tests/assets/config.sepolia.yaml

@@ -1,7 +1,7 @@
 beacon_url: http://localhost:3500/
 beacon_timeout_sec: 90
 network: sepolia
-metrics_port: 4242
+metrics_port: 8000
 
 # We have data for:
 #

tests/test_sepolia.py

@@ -1,4 +1,5 @@
 import os
+import requests
 import vcr
 
 from pathlib import Path
@@ -17,30 +18,61 @@ class SepoliaTestCase(VCRTestCase):
     - slot 5493884 (timestamp=1721660208)
     - slot 6356780 (timestamp=1721661324)
     """
+
+    def get_metrics(self):
+        url = 'http://localhost:8000/metrics'
+        response = requests.get(url)
+        self.assertEqual(response.status_code, 200)
+        result = {}
+        for line in response.text.split('\n'):
+            line = line.strip()
+            if line and not line.startswith('#'):
+                key, value = line.split(' ')
+                result[key] = float(value)
+        return result
+
     def slot_5493884(self):
-        pass
+        metrics = self.get_metrics()
+
+        self.assertEqual(metrics['eth_slot{network="sepolia"}'], 5493884.0)
+        self.assertEqual(metrics['eth_epoch{network="sepolia"}'], 171683.0)
+
+    def slot_5493887(self):
+        metrics = self.get_metrics()
+
+        self.assertEqual(metrics['eth_slot{network="sepolia"}'], 5493887.0)
+        self.assertEqual(metrics['eth_epoch{network="sepolia"}'], 171683.0)
 
-    @vcr.use_cassette('tests/assets/cassettes/test_sepolia.yaml')
     def test_sepolia(self):
         """Main entrypoint for entire Sepolia unit test.
         """
-        self.watcher = ValidatorWatcher(
-            Path(assets.__file__).parent / "config.sepolia.yaml"
-        )
 
-        callbacks = {
-            5493884: self.slot_5493884
-        }
+        def ignore_metrics_cb(request):
+            if request.uri == 'http://localhost:8000/metrics':
+                return None
+            return request
+
+        v = vcr.VCR(before_record=ignore_metrics_cb)
+
+        with v.use_cassette('tests/assets/cassettes/test_sepolia.yaml'):
+            self.watcher = ValidatorWatcher(
+                Path(assets.__file__).parent / "config.sepolia.yaml"
+            )
+
+            callbacks = {
+                5493884: self.slot_5493884,
+                5493887: self.slot_5493887,
+            }
 
-        called = {}
+            called = {}
 
-        def slot_hook(slot: int):
-            if slot in callbacks:
-                callbacks[slot]()
-                called[slot] = True
+            def slot_hook(slot: int):
+                if slot in callbacks:
+                    callbacks[slot]()
+                    called[slot] = True
 
-        self.watcher._slot_hook = slot_hook
-        self.watcher.run()
+            self.watcher._slot_hook = slot_hook
+            self.watcher.run()
 
-        for slot in callbacks.keys():
-            self.assertTrue(called.get(slot))
+            for slot in callbacks.keys():
+                self.assertTrue(called.get(slot))