Simplify CanonicalOwnerIdRegistry impl

src/main/kotlin/com/atlassian/performance/tools/aws/CanonicalOwnerIdRegistry.kt

@@ -1,20 +1,15 @@
 package com.atlassian.performance.tools.aws
 
 import com.amazonaws.regions.Regions
+import com.amazonaws.regions.Regions.*
 
 /**
- * Based on https://ubuntu.com/server/docs/cloud-images/amazon-ec2
+ * Based on https://documentation.ubuntu.com/aws/en/latest/aws-how-to/instances/find-ubuntu-images/#ownership-verification
  */
 internal object CanonicalOwnerIdRegistry {
-    const val default = "099720109477"
-    val byRegion = Regions.values().associate {
-        it to when(it) {
-            Regions.GovCloud -> "513442679011"
-            Regions.CN_NORTH_1,
-            Regions.CN_NORTHWEST_1 -> "837727238323"
-            else -> default
-        }
+    fun forRegion(region: Regions?) = when (region) {
+        GovCloud -> "513442679011"
+        CN_NORTH_1, CN_NORTHWEST_1 -> "837727238323"
+        else -> "099720109477"
     }
-
-    fun forRegion(region: Regions?) = byRegion[region] ?: default
 }

src/test/kotlin/com/atlassian/performance/tools/aws/api/CanonicalImageIdByNameResolverTest.kt

@@ -36,7 +36,7 @@ class CanonicalImageIdByNameResolverTest {
             assertThat(savedRequest).isNotNull
             assertThat(savedRequest!!.filters).contains(
                 Filter("name", listOf(queriedImageName)),
-                Filter("owner-id", listOf(CanonicalOwnerIdRegistry.byRegion[region]))
+                Filter("owner-id", listOf(CanonicalOwnerIdRegistry.forRegion(region)))
             )
         }
     }
@@ -63,7 +63,7 @@ class CanonicalImageIdByNameResolverTest {
         assertThat(savedRequest).isNotNull
         assertThat(savedRequest!!.filters).contains(
             Filter("name", listOf(queriedImageName)),
-            Filter("owner-id", listOf(CanonicalOwnerIdRegistry.default))
+            Filter("owner-id", listOf("099720109477"))
         )
     }