[apm-server]Fix fullnameOverride setting

apm-server/templates/_helpers.tpl

@@ -11,9 +11,13 @@ Create a default fully qualified app name.
 We truncate at 63 chars because some Kubernetes name fields are limited to this (by the DNS naming spec).
 */}}
 {{- define "apm.fullname" }}
+{{- if .Values.fullnameOverride -}}
+{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" -}}
+{{- else -}}
 {{- $name := default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-"}}
 {{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" -}}
 {{- end -}}
+{{- end -}}
 
 {{/*
 Return the appropriate apiVersion for ingress.

apm-server/tests/apmserver_test.py

@@ -296,3 +296,21 @@ def test_priority_class_name():
         "priorityClassName"
     ]
     assert priority_class_name == "highest"
+
+
+def test_setting_fullnameOverride():
+    config = """
+fullnameOverride: "apm-server-custom"
+"""
+    r = helm_template(config)
+
+    custom_name = 'apm-server-custom'
+    assert custom_name in r["deployment"]
+    assert custom_name in r["service"]
+
+    assert (
+        r["deployment"][custom_name]["spec"]["template"]["spec"]["containers"][0][
+            "name"
+        ]
+        == project
+    )