feat: add MySQL reader and writer

pkg/readers/mysql/reader_test.go

@@ -0,0 +1,21 @@
+package mysql
+
+import (
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+	"testing"
+)
+
+func TestReaderMapDataType(t *testing.T) {
+	r := NewReader(&readers.ReaderOptions{})
+	for _, tc := range []struct{ input, want string }{{"varchar(64)", "string"}, {"bigint unsigned", "int64"}, {"datetime", "timestamp"}, {"json", "json"}} {
+		if got := r.mapDataType(tc.input); got != tc.want {
+			t.Errorf("mapDataType(%q) = %q, want %q", tc.input, got, tc.want)
+		}
+	}
+}
+
+func TestReaderRequiresConnectionString(t *testing.T) {
+	if _, err := NewReader(&readers.ReaderOptions{}).ReadDatabase(); err == nil {
+		t.Fatal("expected missing connection string error")
+	}
+}