Ensure default customization of Chart dependencies (#748)

### Description of the change

This adds unittests for the default configuration of our dependencies.

### Benefits

We are able to detect changes in upstream Charts for those settings.

### Applicable issues

- fixes #409

### Additional information

I merged existing unittests with the new ones for `postgresql-ha` and `postgresql`.
However, I decided to not do this for `redis-cluster` and `redis`, because the existing tests[^1] also ensure how the Chart behaves when both redis dependencies are disabled. It didn't felt right to split those files.

### Checklist

- [x] Templating unittests are added

Signed-off-by: justusbunsi <sk.bunsenbrenner@gmail.com>

[^1]: e733287dc2/unittests/config/cache-config.yaml, e733287dc2/unittests/config/queue-config.yaml, e733287dc2/unittests/config/session-config.yaml

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/748
Co-authored-by: justusbunsi <sk.bunsenbrenner@gmail.com>
Co-committed-by: justusbunsi <sk.bunsenbrenner@gmail.com>

unittests/dependency-checks/customization-integrity-postgresql.yaml

@@ -0,0 +1,88 @@
+suite: Dependency checks | Customization integrity | postgresql
+release:
+  name: gitea-unittests
+  namespace: testing
+set:
+  postgresql-ha:
+    enabled: false
+  postgresql:
+    enabled: true
+    global:
+      postgresql:
+        auth:
+          password: gitea-password
+          database: gitea-database
+          username: gitea-username
+        service:
+          ports:
+            postgresql: 1234
+    primary:
+      persistence:
+        size: 1337Mi
+tests:
+  - it: "[postgresql] DB settings are applied as expected"
+    template: charts/postgresql/templates/primary/statefulset.yaml
+    asserts:
+      - documentIndex: 0
+        contains:
+          path: spec.template.spec.containers[0].env
+          content:
+            name: POSTGRES_DATABASE
+            value: "gitea-database"
+      - documentIndex: 0
+        contains:
+          path: spec.template.spec.containers[0].env
+          content:
+            name: POSTGRES_USER
+            value: "gitea-username"
+  - it: "[postgresql] DB password is applied as expected"
+    template: charts/postgresql/templates/secrets.yaml
+    asserts:
+      - documentIndex: 0
+        equal:
+          path: data["password"]
+          value: "Z2l0ZWEtcGFzc3dvcmQ="
+  - it: "[postgresql] primary.persistence.size is applied as expected"
+    template: charts/postgresql/templates/primary/statefulset.yaml
+    asserts:
+      - documentIndex: 0
+        equal:
+          path: spec.volumeClaimTemplates[0].spec.resources.requests.storage
+          value: "1337Mi"
+  - it: "[postgresql] global.postgresql.service.ports.postgresql is applied as expected"
+    template: charts/postgresql/templates/primary/svc.yaml
+    asserts:
+      - documentIndex: 0
+        equal:
+          path: spec.ports[0].port
+          value: 1234
+  - it: "[postgresql] renders the referenced service"
+    template: charts/postgresql/templates/primary/svc.yaml
+    asserts:
+      - containsDocument:
+          kind: Service
+          apiVersion: v1
+          name: gitea-unittests-postgresql
+          namespace: testing
+  - it: "[gitea] connects to postgresql service"
+    template: templates/gitea/config.yaml
+    asserts:
+      - documentIndex: 0
+        matchRegex:
+          path: stringData.database
+          pattern: HOST=gitea-unittests-postgresql.testing.svc.cluster.local:1234
+  - it: "[gitea] connects to configured database"
+    template: templates/gitea/config.yaml
+    asserts:
+      - documentIndex: 0
+        matchRegex:
+          path: stringData.database
+          pattern: NAME=gitea-database
+      - documentIndex: 0
+        matchRegex:
+          path: stringData.database
+          pattern: USER=gitea-username
+      - documentIndex: 0
+        matchRegex:
+          path: stringData.database
+          pattern: PASSWD=gitea-password