test(probes): add startup probe tests and deployment notes

Add helm-unittest tests for startup probe:
- Default configuration verification (tcpSocket, timing)
- Custom timing parameters (initialDelaySeconds, periodSeconds, failureThreshold)
- Alternative probe types (httpGet)
- Custom port support
- Timeout window calculation

Add NOTES.txt with startup probe information:
- Display max startup time calculation
- Explain startup probe purpose for large libraries
- Warning for very long startup timeouts

Tests ensure startup probe works correctly for slow initial startup scenarios.

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Aleksei Sviridkin <f@lex.la>

charts/jellyfin/tests/startup_probe_test.yaml

@@ -0,0 +1,92 @@
+suite: test startup probe
+templates:
+  - deployment.yaml
+tests:
+  - it: should have startup probe by default
+    asserts:
+      - isNotNull:
+          path: spec.template.spec.containers[0].startupProbe
+
+  - it: should use tcpSocket by default
+    asserts:
+      - isNotNull:
+          path: spec.template.spec.containers[0].startupProbe.tcpSocket
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.tcpSocket.port
+          value: http
+
+  - it: should have default timing values
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.initialDelaySeconds
+          value: 0
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.periodSeconds
+          value: 10
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.failureThreshold
+          value: 30
+
+  - it: should allow custom initialDelaySeconds
+    set:
+      startupProbe.initialDelaySeconds: 5
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.initialDelaySeconds
+          value: 5
+
+  - it: should allow custom periodSeconds
+    set:
+      startupProbe.periodSeconds: 15
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.periodSeconds
+          value: 15
+
+  - it: should allow custom failureThreshold
+    set:
+      startupProbe.failureThreshold: 60
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.failureThreshold
+          value: 60
+
+  - it: should support httpGet probe
+    set:
+      startupProbe:
+        httpGet:
+          path: /health
+          port: http
+        initialDelaySeconds: 0
+        periodSeconds: 10
+        failureThreshold: 30
+    asserts:
+      - isNotNull:
+          path: spec.template.spec.containers[0].startupProbe.httpGet
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.httpGet.path
+          value: /health
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.httpGet.port
+          value: http
+
+  - it: should support custom port
+    set:
+      startupProbe.tcpSocket.port: 9000
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.tcpSocket.port
+          value: 9000
+
+  - it: should calculate correct timeout window
+    set:
+      startupProbe.periodSeconds: 10
+      startupProbe.failureThreshold: 30
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.periodSeconds
+          value: 10
+      - equal:
+          path: spec.template.spec.containers[0].startupProbe.failureThreshold
+          value: 30
+    # Total startup time allowed: 10 * 30 = 300 seconds (5 minutes)