fix #230: Fix schema (in)sensitive casing issue

grate/Migration/AnsiSqlDatabase.cs

@@ -279,7 +279,7 @@ private async Task<bool> RunSchemaExists()
     {
         string sql = $"SELECT s.SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA s WHERE s.SCHEMA_NAME = '{SchemaName}'";
         var res = await ExecuteScalarAsync<string>(ActiveConnection, sql);
-        return res == SchemaName;
+        return res != null; // #230: If the server found a record that's good enough for us
     }
 
     // TODO: Change MySQL/MariaDB from using schemas to using grate_ prefix

grate/Migration/PostgreSqlDatabase.cs

@@ -27,4 +27,18 @@ public override Task RestoreDatabase(string backupPath)
 
     public override IEnumerable<string> GetStatements(string sql)
         => ReflectionNpgsqlQueryParser.Split(sql);
+
+    protected override string ExistsSql(string tableSchema, string fullTableName)
+    {
+        // For #230.  Postgres tables are lowercase by default unless you quote them when created, which we do.  We _don't_ quote the schema though, so it will always be lowercase
+        // Ensure the table check uses the lowercase version of anything we're passed, as that's what we would have created.
+        return base.ExistsSql(tableSchema.ToLower(), fullTableName);
+    }
+
+    protected override string ExistsSql(string tableSchema, string fullTableName, string columnName)
+    {
+        // For #230.  Postgres tables are lowercase by default unless you quote them when created, which we do.  We _don't_ quote the schema though, so it will always be lowercase
+        // Ensure the table check uses the lowercase version of anything we're passed, as that's what we would have created.
+        return base.ExistsSql(tableSchema.ToLower(), fullTableName, columnName);
+    }
 }

unittests/TestCommon/Generic/Running_MigrationScripts/Versioning_The_Database.cs

@@ -94,4 +94,33 @@ public async Task Creates_a_new_version_with_status_InProgress()
         var version = entries.Single(x => x.version == dbVersion);
         version.status.Should().Be(MigrationStatus.InProgress);
     }
+
+    [Test]
+    public async Task Bug230_Uses_Server_Casing_Rules_For_Schema()
+    {
+        //for bug #230 - when targeting an existing schema use the servers casing rules, not .Net's
+        var db = TestConfig.RandomDatabase();
+        var parent = CreateRandomTempDirectory();
+        var knownFolders = FoldersConfiguration.Default(null);
+
+        CreateDummySql(parent, knownFolders[Sprocs]); // make sure there's something that could be logged...
+
+        await using (var migrator = Context.GetMigrator(db, parent, knownFolders))
+        {
+            await migrator.Migrate();
+            Assert.True(await migrator.DbMigrator.Database.VersionTableExists()); // we migrated into the `grate` schema.
+        }
+
+        // Now we'll run again with the same name but different cased schema
+        var grateConfig = Context.GetConfiguration(db, parent, knownFolders) with
+        {
+            SchemaName = "GRATE"
+        };
+
+        await using (var migrator = Context.GetMigrator(grateConfig))
+        {
+            await migrator.Migrate(); // should either reuse the existing schema if a case-insensitive server, or create a new second schema for use if case-sensitive.
+            Assert.True(await migrator.DbMigrator.Database.VersionTableExists()); // we migrated into the `GRATE` schema, which may be the same as 'grate' depending on server settings.
+        }
+    }
 }