GODRIVER-3444 Add tests for CalculateMaxTimeMS

Author: prestonvasquez

internal/driverutil/operation_test.go

@@ -0,0 +1,107 @@
+package driverutil
+
+import (
+	"context"
+	"math"
+	"testing"
+	"time"
+
+	"go.mongodb.org/mongo-driver/v2/internal/assert"
+)
+
+//nolint:govet
+func TestCalculateMaxTimeMS(t *testing.T) {
+	tests := []struct {
+		name         string
+		ctx          context.Context
+		rttMin       time.Duration
+		wantZero     bool
+		wantOk       bool
+		wantPositive bool
+		wantExact    int64
+	}{
+		{
+			name:         "no deadline",
+			ctx:          context.Background(),
+			rttMin:       10 * time.Millisecond,
+			wantZero:     true,
+			wantOk:       true,
+			wantPositive: false,
+		},
+		{
+			name: "deadline expired",
+			ctx: func() context.Context {
+				ctx, _ := context.WithDeadline(context.Background(), time.Now().Add(-1*time.Second)) //nolint:govet
+				return ctx
+			}(),
+			wantZero:     true,
+			wantOk:       false,
+			wantPositive: false,
+		},
+		{
+			name: "remaining timeout < rttMin",
+			ctx: func() context.Context {
+				ctx, _ := context.WithDeadline(context.Background(), time.Now().Add(1*time.Millisecond))
+				return ctx
+			}(),
+			rttMin:       10 * time.Millisecond,
+			wantZero:     true,
+			wantOk:       false,
+			wantPositive: false,
+		},
+		{
+			name: "normal positive result",
+			ctx: func() context.Context {
+				ctx, _ := context.WithDeadline(context.Background(), time.Now().Add(100*time.Millisecond))
+				return ctx
+			}(),
+			wantZero:     false,
+			wantOk:       true,
+			wantPositive: true,
+		},
+		{
+			name: "beyond maxInt32",
+			ctx: func() context.Context {
+				ctx, _ := context.WithDeadline(context.Background(), time.Now().Add(time.Duration(math.MaxInt32+1000)*time.Millisecond))
+				return ctx
+			}(),
+			wantZero:     true,
+			wantOk:       true,
+			wantPositive: false,
+		},
+		{
+			name: "round up to 1ms",
+			ctx: func() context.Context {
+				ctx, _ := context.WithDeadline(context.Background(), time.Now().Add(999*time.Microsecond))
+				return ctx
+			}(),
+			wantOk:    true,
+			wantExact: 1,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, got1 := CalculateMaxTimeMS(tt.ctx, tt.rttMin)
+
+			assert.Equal(t, tt.wantOk, got1)
+
+			if tt.wantExact > 0 && got != tt.wantExact {
+				t.Errorf("CalculateMaxTimeMS() got = %v, want %v", got, tt.wantExact)
+			}
+
+			if tt.wantZero && got != 0 {
+				t.Errorf("CalculateMaxTimeMS() got = %v, want 0", got)
+			}
+
+			if !tt.wantZero && got == 0 {
+				t.Errorf("CalculateMaxTimeMS() got = %v, want > 0", got)
+			}
+
+			if !tt.wantZero && tt.wantPositive && got <= 0 {
+				t.Errorf("CalculateMaxTimeMS() got = %v, want > 0", got)
+			}
+		})
+	}
+
+}