Add unit tests for event-counters cli (#2)

tests/event_counters_input/counters_db.json

@@ -0,0 +1,18 @@
+{
+    "COUNTERS_EVENTS:latency_in_ms": {
+        "value": 2
+    },
+    "COUNTERS_EVENTS:missed_to_cache": {
+        "value": 0
+    },
+    "COUNTERS_EVENTS:missed_internal": {
+        "value": 0
+    },
+    "COUNTERS_EVENTS:missed_by_slow_receiver": {
+        "value": 0
+    },
+    "COUNTERS_EVENTS:published": {
+        "value": 40147
+    }
+}
+

tests/show_event_counters.py

@@ -0,0 +1,37 @@
+import os
+import sys
+from click.testing import CliRunner
+from utilities_common.db import Db
+import show.main as show
+
+class TestShowEventCounters(object):
+    @classmethod
+    def setup_class(cls):
+        print("SETUP")
+        os.environ["UTILITIES_UNIT_TESTING"] = "1"
+
+    def test_event_counters_show(self):
+        from .mock_tables import dbconnector
+        test_path = os.path.dirname(os.path.abspath(__file__))
+        mock_db_path = os.path.join(test_path, "event_counters_input")
+        jsonfile_counters = os.path.join(mock_db_path, "counters_db")
+        dbconnector.dedicated_dbs['COUNTERS_DB'] = jsonfile_counters
+        runner = CliRunner()
+        db = Db()
+        expected_output = """\
+                   name    count
+-----------------------  -------
+          latency_in_ms        2
+missed_by_slow_receiver        0
+        missed_internal        0
+        missed_to_cache        0
+              published    40147
+"""
+
+        result = runner.invoke(show.cli.commands['event-counters'], [], obj=db)
+        print(result.exit_code)
+        print(result.output)
+        dbconnector.dedicated_dbs['COUNTERS_DB'] = None
+        assert result.exit_code == 0
+        assert result.output == expected_output
+