Unit tests for active instance store

Author: simolus3

core/src/commonMain/kotlin/com/powersync/db/ActiveInstanceStore.kt

@@ -42,7 +42,7 @@ internal class ActiveDatabaseGroup(
             Please check your PowerSync client instantiation logic if this is not intentional.
             """.trimIndent()
 
-        private val allGroups = mutableListOf<ActiveDatabaseGroup>()
+        internal val allGroups = mutableListOf<ActiveDatabaseGroup>()
 
         private fun findGroup(
             warnOnDuplicate: Logger,

core/src/commonTest/kotlin/com/powersync/db/ActiveDatabaseGroupTest.kt

@@ -0,0 +1,79 @@
+package com.powersync.db
+
+import co.touchlab.kermit.ExperimentalKermitApi
+import co.touchlab.kermit.Logger
+import co.touchlab.kermit.Severity
+import co.touchlab.kermit.TestConfig
+import co.touchlab.kermit.TestLogWriter
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
+
+@OptIn(ExperimentalKermitApi::class)
+class ActiveDatabaseGroupTest {
+
+    private val logWriter =
+        TestLogWriter(
+            loggable = Severity.Debug,
+        )
+
+    private val logger =
+        Logger(
+            TestConfig(
+                minSeverity = Severity.Debug,
+                logWriterList = listOf(logWriter),
+            ),
+        )
+
+    @BeforeTest
+    fun setupDatabase() {
+        logWriter.reset()
+    }
+
+    @Test
+    fun testTrackDatabase() {
+        val usage = ActiveDatabaseGroup.referenceDatabase(logger, "test")
+        assertEquals(1, ActiveDatabaseGroup.allGroups.size)
+
+        usage.first.dispose()
+        assertEquals(0, ActiveDatabaseGroup.allGroups.size)
+    }
+
+    @Test
+    fun testWarnsOnDuplicate() {
+        val usage = ActiveDatabaseGroup.referenceDatabase(logger, "test")
+        assertEquals(1, ActiveDatabaseGroup.allGroups.size)
+
+        assertEquals(0, logWriter.logs.size)
+
+        val another = ActiveDatabaseGroup.referenceDatabase(logger, "test")
+        assertNotNull(
+            logWriter.logs.find {
+                it.message == ActiveDatabaseGroup.multipleInstancesMessage
+            },
+        )
+
+        assertEquals(usage.first.group, another.first.group)
+
+        usage.first.dispose()
+        assertEquals(1, ActiveDatabaseGroup.allGroups.size)
+        another.first.dispose()
+        assertEquals(0, ActiveDatabaseGroup.allGroups.size)
+    }
+
+    @Test
+    fun testDoesNotWarnForDifferentIdentifiers() {
+        val usage = ActiveDatabaseGroup.referenceDatabase(logger, "test")
+        assertEquals(1, ActiveDatabaseGroup.allGroups.size)
+        val another = ActiveDatabaseGroup.referenceDatabase(logger, "test2")
+        assertEquals(2, ActiveDatabaseGroup.allGroups.size)
+
+        assertEquals(0, logWriter.logs.size)
+
+        usage.first.dispose()
+        assertEquals(1, ActiveDatabaseGroup.allGroups.size)
+        another.first.dispose()
+        assertEquals(0, ActiveDatabaseGroup.allGroups.size)
+    }
+}