Fix PostgresError conformance to DatabaseError (#143)

* fix PostgresError conformance to DatabaseError

* delete linux test files

Author: madsodgaard

Sources/FluentPostgresDriver/PostgresError+Database.swift

@@ -2,14 +2,72 @@ import FluentSQL
 
 extension PostgresError: DatabaseError {
     public var isSyntaxError: Bool {
-        return false
+        switch self.code {
+        case .syntaxErrorOrAccessRuleViolation,
+             .syntaxError,
+             .insufficientPrivilege,
+             .cannotCoerce,
+             .groupingError,
+             .windowingError,
+             .invalidRecursion,
+             .invalidForeignKey,
+             .invalidName,
+             .nameTooLong,
+             .reservedName,
+             .datatypeMismatch,
+             .indeterminateDatatype,
+             .collationMismatch,
+             .indeterminateCollation,
+             .wrongObjectType,
+             .undefinedColumn,
+             .undefinedFunction,
+             .undefinedTable,
+             .undefinedParameter,
+             .undefinedObject,
+             .duplicateColumn,
+             .duplicateCursor,
+             .duplicateDatabase,
+             .duplicateFunction,
+             .duplicatePreparedStatement,
+             .duplicateSchema,
+             .duplicateTable,
+             .duplicateAlias,
+             .duplicateObject,
+             .ambiguousColumn,
+             .ambiguousFunction,
+             .ambiguousParameter,
+             .ambiguousAlias,
+             .invalidColumnReference,
+             .invalidColumnDefinition,
+             .invalidCursorDefinition,
+             .invalidDatabaseDefinition,
+             .invalidFunctionDefinition,
+             .invalidPreparedStatementDefinition,
+             .invalidSchemaDefinition,
+             .invalidTableDefinition,
+             .invalidObjectDefinition:
+            return true
+        default:
+            return false
+        }
     }
-
+    
     public var isConnectionClosed: Bool {
         return false
     }
-
+    
     public var isConstraintFailure: Bool {
-        return false
+        switch self.code {
+        case .integrityConstraintViolation,
+             .restrictViolation,
+             .notNullViolation,
+             .foreignKeyViolation,
+             .uniqueViolation,
+             .checkViolation,
+             .exclusionViolation:
+            return true
+        default:
+            return false
+        }
     }
 }

Tests/FluentPostgresDriverTests/FluentPostgresDriverTests.swift

@@ -33,6 +33,26 @@ final class FluentPostgresDriverTests: XCTestCase {
     func testTransaction() throws { try self.benchmarker.testTransaction() }
     func testUnique() throws { try self.benchmarker.testUnique() }
 
+    func testDatabaseError() throws {
+        let sql = (self.db as! SQLDatabase)
+        do {
+            try sql.raw("asd").run().wait()
+        } catch let error as DatabaseError where error.isSyntaxError {
+            // PASS
+        } catch {
+            XCTFail("\(error)")
+        }
+        do {
+            try sql.raw("CREATE TABLE foo (name TEXT UNIQUE)").run().wait()
+            try sql.raw("INSERT INTO foo (name) VALUES ('bar')").run().wait()
+            try sql.raw("INSERT INTO foo (name) VALUES ('bar')").run().wait()
+        } catch let error as DatabaseError where error.isConstraintFailure {
+            // pass
+        } catch {
+            XCTFail("\(error)")
+        }
+    }
+    
     func testBlob() throws {
         final class Foo: Model {
             static let schema = "foos"