Add required tests for go/mysql/format

Signed-off-by: Noble Mittal <[email protected]>

go/mysql/format/float_test.go

@@ -0,0 +1,42 @@
+/*
+Copyright 2024 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package format
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFormatFloat(t *testing.T) {
+	testCases := []struct {
+		input float64
+		want  []byte
+	}{
+		{123.456, []byte("123.456")},
+		{-1.13456e15, []byte("-1.13456e15")},
+		{2e15, []byte("2e15")},
+		{2e-15, []byte("0.000000000000002")},
+		{-1e-16, []byte("-1e-16")},
+		{0.0, []byte("0")},
+	}
+
+	for _, tCase := range testCases {
+		got := FormatFloat(tCase.input)
+		assert.Equal(t, tCase.want, got)
+	}
+}