diff --git a/tests/lib/DB/MigrationsTest.php b/tests/lib/DB/MigrationsTest.php
index 7e20119108742..8654c83a545a8 100644
--- a/tests/lib/DB/MigrationsTest.php
+++ b/tests/lib/DB/MigrationsTest.php
@@ -16,6 +16,7 @@
 use Doctrine\DBAL\Schema\ForeignKeyConstraint;
 use Doctrine\DBAL\Schema\Index;
 use Doctrine\DBAL\Schema\Schema;
+use Doctrine\DBAL\Schema\SchemaException;
 use Doctrine\DBAL\Schema\Sequence;
 use Doctrine\DBAL\Schema\Table;
 use OC\DB\Connection;
@@ -102,13 +103,12 @@ public function testExecuteStepWithSchemaChange() {
 			->method('migrateToSchema');
 
 		$wrappedSchema = $this->createMock(Schema::class);
-		// TODO re-enable once stable14 is branched of: https://github.com/nextcloud/server/issues/10518
-		/*$wrappedSchema->expects($this->once())
+		$wrappedSchema->expects($this->once())
 			->method('getTables')
 			->willReturn([]);
 		$wrappedSchema->expects($this->once())
 			->method('getSequences')
-			->willReturn([]);*/
+			->willReturn([]);
 
 		$schemaResult = $this->createMock(SchemaWrapper::class);
 		$schemaResult->expects($this->once())
@@ -239,12 +239,12 @@ public function testEnsureOracleIdentifierLengthLimitValid() {
 			->willReturn(\str_repeat('a', 30));
 
 		$table = $this->createMock(Table::class);
-		$table->expects($this->once())
+		$table->expects($this->atLeastOnce())
 			->method('getName')
 			->willReturn(\str_repeat('a', 30));
 
 		$sequence = $this->createMock(Sequence::class);
-		$sequence->expects($this->once())
+		$sequence->expects($this->atLeastOnce())
 			->method('getName')
 			->willReturn(\str_repeat('a', 30));
 
@@ -269,7 +269,15 @@ public function testEnsureOracleIdentifierLengthLimitValid() {
 			->method('getSequences')
 			->willReturn([$sequence]);
 
-		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$schema, 3]);
+		$sourceSchema = $this->createMock(Schema::class);
+		$sourceSchema->expects($this->any())
+			->method('getTable')
+			->willThrowException(new SchemaException());
+		$sourceSchema->expects($this->any())
+			->method('hasSequence')
+			->willReturn(false);
+
+		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$sourceSchema, $schema, 3]);
 	}
 
 	public function testEnsureOracleIdentifierLengthLimitValidWithPrimaryKey() {
@@ -304,7 +312,15 @@ public function testEnsureOracleIdentifierLengthLimitValidWithPrimaryKey() {
 			->method('getSequences')
 			->willReturn([]);
 
-		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$schema, 3]);
+		$sourceSchema = $this->createMock(Schema::class);
+		$sourceSchema->expects($this->any())
+			->method('getTable')
+			->willThrowException(new SchemaException());
+		$sourceSchema->expects($this->any())
+			->method('hasSequence')
+			->willReturn(false);
+
+		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$sourceSchema, $schema, 3]);
 	}
 
 	public function testEnsureOracleIdentifierLengthLimitValidWithPrimaryKeyDefault() {
@@ -349,7 +365,15 @@ public function testEnsureOracleIdentifierLengthLimitValidWithPrimaryKeyDefault(
 			->method('getSequences')
 			->willReturn([]);
 
-		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$schema, 3]);
+		$sourceSchema = $this->createMock(Schema::class);
+		$sourceSchema->expects($this->any())
+			->method('getTable')
+			->willThrowException(new SchemaException());
+		$sourceSchema->expects($this->any())
+			->method('hasSequence')
+			->willReturn(false);
+
+		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$sourceSchema, $schema, 3]);
 	}
 
 	/**
@@ -366,7 +390,15 @@ public function testEnsureOracleIdentifierLengthLimitTooLongTableName() {
 			->method('getTables')
 			->willReturn([$table]);
 
-		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$schema, 3]);
+		$sourceSchema = $this->createMock(Schema::class);
+		$sourceSchema->expects($this->any())
+			->method('getTable')
+			->willThrowException(new SchemaException());
+		$sourceSchema->expects($this->any())
+			->method('hasSequence')
+			->willReturn(false);
+
+		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$sourceSchema, $schema, 3]);
 	}
 
 	/**
@@ -411,7 +443,15 @@ public function testEnsureOracleIdentifierLengthLimitTooLongPrimaryWithDefault()
 			->method('getTables')
 			->willReturn([$table]);
 
-		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$schema, 3]);
+		$sourceSchema = $this->createMock(Schema::class);
+		$sourceSchema->expects($this->any())
+			->method('getTable')
+			->willThrowException(new SchemaException());
+		$sourceSchema->expects($this->any())
+			->method('hasSequence')
+			->willReturn(false);
+
+		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$sourceSchema, $schema, 3]);
 	}
 
 	/**
@@ -446,7 +486,15 @@ public function testEnsureOracleIdentifierLengthLimitTooLongPrimaryWithName() {
 			->method('getTables')
 			->willReturn([$table]);
 
-		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$schema, 3]);
+		$sourceSchema = $this->createMock(Schema::class);
+		$sourceSchema->expects($this->any())
+			->method('getTable')
+			->willThrowException(new SchemaException());
+		$sourceSchema->expects($this->any())
+			->method('hasSequence')
+			->willReturn(false);
+
+		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$sourceSchema, $schema, 3]);
 	}
 
 	/**
@@ -472,7 +520,15 @@ public function testEnsureOracleIdentifierLengthLimitTooLongColumnName() {
 			->method('getTables')
 			->willReturn([$table]);
 
-		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$schema, 3]);
+		$sourceSchema = $this->createMock(Schema::class);
+		$sourceSchema->expects($this->any())
+			->method('getTable')
+			->willThrowException(new SchemaException());
+		$sourceSchema->expects($this->any())
+			->method('hasSequence')
+			->willReturn(false);
+
+		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$sourceSchema, $schema, 3]);
 	}
 
 	/**
@@ -501,7 +557,15 @@ public function testEnsureOracleIdentifierLengthLimitTooLongIndexName() {
 			->method('getTables')
 			->willReturn([$table]);
 
-		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$schema, 3]);
+		$sourceSchema = $this->createMock(Schema::class);
+		$sourceSchema->expects($this->any())
+			->method('getTable')
+			->willThrowException(new SchemaException());
+		$sourceSchema->expects($this->any())
+			->method('hasSequence')
+			->willReturn(false);
+
+		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$sourceSchema, $schema, 3]);
 	}
 
 	/**
@@ -533,7 +597,15 @@ public function testEnsureOracleIdentifierLengthLimitTooLongForeignKeyName() {
 			->method('getTables')
 			->willReturn([$table]);
 
-		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$schema, 3]);
+		$sourceSchema = $this->createMock(Schema::class);
+		$sourceSchema->expects($this->any())
+			->method('getTable')
+			->willThrowException(new SchemaException());
+		$sourceSchema->expects($this->any())
+			->method('hasSequence')
+			->willReturn(false);
+
+		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$sourceSchema, $schema, 3]);
 	}
 
 	/**
@@ -553,6 +625,14 @@ public function testEnsureOracleIdentifierLengthLimitTooLongSequenceName() {
 			->method('getSequences')
 			->willReturn([$sequence]);
 
-		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$schema, 3]);
+		$sourceSchema = $this->createMock(Schema::class);
+		$sourceSchema->expects($this->any())
+			->method('getTable')
+			->willThrowException(new SchemaException());
+		$sourceSchema->expects($this->any())
+			->method('hasSequence')
+			->willReturn(false);
+
+		self::invokePrivate($this->migrationService, 'ensureOracleIdentifierLengthLimit', [$sourceSchema, $schema, 3]);
 	}
 }