Add failing test for merged migration that merges itself

Author: groue

Tests/GRDBTests/DatabaseMigratorTests.swift

@@ -1282,6 +1282,122 @@ class DatabaseMigratorTests : GRDBTestCase {
         }
     }
 
+    func test_merged_migrations_named_like_the_last_that_includes_itself_in_the_list_of_merged_migrations() throws {
+        // Original migrator
+        var oldMigrator = DatabaseMigrator()
+        oldMigrator.registerMigration("v1") { db in
+            try db.execute(sql: "CREATE TABLE t1(a)")
+        }
+        oldMigrator.registerMigration("v2") { db in
+            try db.execute(sql: "CREATE TABLE t2(a)")
+        }
+        oldMigrator.registerMigration("v3") { db in
+            try db.execute(sql: "CREATE TABLE t3(a)")
+        }
+        oldMigrator.registerMigration("v4") { db in
+            try db.execute(sql: "CREATE TABLE t4(a)")
+        }
+        oldMigrator.registerMigration("v5") { db in
+            try db.execute(sql: "CREATE TABLE t5(a)")
+        }
+        
+        // New migrator merges v2, v3, and v4 into v4
+        var newMigrator = DatabaseMigrator()
+        newMigrator.registerMigration("v1") { db in
+            try db.execute(sql: "CREATE TABLE t1(a)")
+        }
+        // SUT: the migration identifier is included in the list of merged identifiers.
+        newMigrator.registerMigration("v4", merging: ["v2", "v3", "v4"]) { db, appliedIDs in
+            if !appliedIDs.contains("v2") {
+                try db.execute(sql: "CREATE TABLE t2(a)")
+            }
+            if !appliedIDs.contains("v3") {
+                try db.execute(sql: "CREATE TABLE t3(a)")
+            }
+            try db.execute(sql: "CREATE TABLE t4(a)")
+        }
+        newMigrator.registerMigration("v5") { db in
+            try db.execute(sql: "CREATE TABLE t5(a)")
+        }
+        
+        do {
+            let dbQueue = try makeDatabaseQueue()
+            
+            try newMigrator.migrate(dbQueue)
+            try dbQueue.read { db in
+                try XCTAssertEqual(newMigrator.appliedIdentifiers(db), ["v1", "v4", "v5"])
+                try XCTAssertTrue(String
+                    .fetchSet(db, sql: "SELECT name FROM sqlite_master")
+                    .isSuperset(of: ["t1", "t2", "t3", "t4", "t5"]))
+            }
+        }
+        
+        do {
+            let dbQueue = try makeDatabaseQueue()
+            try oldMigrator.migrate(dbQueue, upTo: "v1")
+            
+            try newMigrator.migrate(dbQueue)
+            try dbQueue.read { db in
+                try XCTAssertEqual(newMigrator.appliedIdentifiers(db), ["v1", "v4", "v5"])
+                try XCTAssertTrue(String
+                    .fetchSet(db, sql: "SELECT name FROM sqlite_master")
+                    .isSuperset(of: ["t1", "t2", "t3", "t4", "t5"]))
+            }
+        }
+        
+        do {
+            let dbQueue = try makeDatabaseQueue()
+            try oldMigrator.migrate(dbQueue, upTo: "v2")
+            
+            try newMigrator.migrate(dbQueue)
+            try dbQueue.read { db in
+                try XCTAssertEqual(newMigrator.appliedIdentifiers(db), ["v1", "v4", "v5"])
+                try XCTAssertTrue(String
+                    .fetchSet(db, sql: "SELECT name FROM sqlite_master")
+                    .isSuperset(of: ["t1", "t2", "t3", "t4", "t5"]))
+            }
+        }
+        
+        do {
+            let dbQueue = try makeDatabaseQueue()
+            try oldMigrator.migrate(dbQueue, upTo: "v3")
+            
+            try newMigrator.migrate(dbQueue)
+            try dbQueue.read { db in
+                try XCTAssertEqual(newMigrator.appliedIdentifiers(db), ["v1", "v4", "v5"])
+                try XCTAssertTrue(String
+                    .fetchSet(db, sql: "SELECT name FROM sqlite_master")
+                    .isSuperset(of: ["t1", "t2", "t3", "t4", "t5"]))
+            }
+        }
+
+        do {
+            let dbQueue = try makeDatabaseQueue()
+            try oldMigrator.migrate(dbQueue, upTo: "v4")
+            
+            try newMigrator.migrate(dbQueue)
+            try dbQueue.read { db in
+                try XCTAssertEqual(newMigrator.appliedIdentifiers(db), ["v1", "v4", "v5"])
+                try XCTAssertTrue(String
+                    .fetchSet(db, sql: "SELECT name FROM sqlite_master")
+                    .isSuperset(of: ["t1", "t2", "t3", "t4", "t5"]))
+            }
+        }
+        
+        do {
+            let dbQueue = try makeDatabaseQueue()
+            try oldMigrator.migrate(dbQueue, upTo: "v5")
+            
+            try newMigrator.migrate(dbQueue)
+            try dbQueue.read { db in
+                try XCTAssertEqual(newMigrator.appliedIdentifiers(db), ["v1", "v4", "v5"])
+                try XCTAssertTrue(String
+                    .fetchSet(db, sql: "SELECT name FROM sqlite_master")
+                    .isSuperset(of: ["t1", "t2", "t3", "t4", "t5"]))
+            }
+        }
+    }
+    
     func test_merged_migrations_with_a_new_name() throws {
         // Original migrator
         var oldMigrator = DatabaseMigrator()