chore(share/getters): add unit test for ctxwithsplittimeout (#2374)

## Overview

Adds extra safety.

Co-authored-by: Hlib Kanunnikov <hlibwondertan@gmail.com>

share/getters/utils_test.go

@@ -1,11 +1,14 @@
 package getters
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func Test_ErrorContains(t *testing.T) {
@@ -101,3 +104,115 @@ func Test_ErrorContains(t *testing.T) {
 		})
 	}
 }
+
+func Test_ctxWithSplitTimeout(t *testing.T) {
+	type args struct {
+		ctxTimeout  time.Duration
+		splitFactor []int
+		minTimeout  time.Duration
+	}
+	tests := []struct {
+		name string
+		args args
+		want time.Duration
+	}{
+		{
+			name: "ctxTimeout > minTimeout, splitFactor <= 0",
+			args: args{
+				ctxTimeout:  3 * time.Minute,
+				splitFactor: []int{-1, 0},
+				minTimeout:  time.Minute,
+			},
+			want: time.Minute,
+		},
+		{
+			name: "ctxTimeout > minTimeout, splitFactor = 1",
+			args: args{
+				ctxTimeout:  3 * time.Minute,
+				splitFactor: []int{1},
+				minTimeout:  time.Minute,
+			},
+			want: 3 * time.Minute,
+		},
+		{
+			name: "ctxTimeout > minTimeout, splitFactor = 2",
+			args: args{
+				ctxTimeout:  3 * time.Minute,
+				splitFactor: []int{2},
+				minTimeout:  time.Minute,
+			},
+			want: 3 * time.Minute / 2,
+		},
+		{
+			name: "ctxTimeout > minTimeout, resulted timeout limited by minTimeout",
+			args: args{
+				ctxTimeout:  3 * time.Minute,
+				splitFactor: []int{3, 4, 5},
+				minTimeout:  time.Minute,
+			},
+			want: time.Minute,
+		},
+		{
+			name: "ctxTimeout < minTimeout",
+			args: args{
+				ctxTimeout:  time.Minute,
+				splitFactor: []int{-1, 0, 1, 2, 3},
+				minTimeout:  2 * time.Minute,
+			},
+			want: time.Minute,
+		},
+		{
+			name: "minTimeout = 0, splitFactor <= 1",
+			args: args{
+				ctxTimeout:  time.Minute,
+				splitFactor: []int{-1, 0, 1},
+				minTimeout:  0,
+			},
+			want: time.Minute,
+		},
+		{
+			name: "minTimeout = 0, splitFactor > 1",
+			args: args{
+				ctxTimeout:  time.Minute,
+				splitFactor: []int{2},
+				minTimeout:  0,
+			},
+			want: time.Minute / 2,
+		},
+		{
+			name: "no context timeout",
+			args: args{
+				ctxTimeout:  0,
+				splitFactor: []int{-1, 0, 1, 2},
+				minTimeout:  time.Minute,
+			},
+			want: 0,
+		},
+		{
+			name: "no context timeout, minTimeout = 0",
+			args: args{
+				ctxTimeout:  0,
+				splitFactor: []int{-1, 0, 1, 2},
+				minTimeout:  0,
+			},
+			want: 0,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			for _, sf := range tt.args.splitFactor {
+				ctx, cancel := context.WithTimeout(context.Background(), tt.args.ctxTimeout)
+				t.Cleanup(cancel)
+				got, _ := ctxWithSplitTimeout(ctx, sf, tt.args.minTimeout)
+				dl, ok := got.Deadline()
+				if !ok {
+					require.Equal(t, tt.want, 0)
+					continue
+				}
+				d := time.Until(dl)
+				require.True(t, d <= tt.want+time.Second)
+				require.True(t, d >= tt.want-time.Second)
+			}
+		})
+	}
+}