Copied mongo repo (to patch it)

mongo/internal/background_context_test.go

@@ -0,0 +1,58 @@
+// Copyright (C) MongoDB, Inc. 2017-present.
+//
+// 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
+
+package internal
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"go.mongodb.org/mongo-driver/internal/testutil/assert"
+)
+
+func TestBackgroundContext(t *testing.T) {
+	t.Run("NewBackgroundContext accepts a nil child", func(t *testing.T) {
+		ctx := NewBackgroundContext(nil)
+		assert.Equal(t, context.Background(), ctx, "expected context.Background() for a nil child")
+	})
+	t.Run("Value requests are forwarded", func(t *testing.T) {
+		// Tests the Value function.
+
+		type ctxKey struct{}
+		expectedVal := "value"
+		childCtx := context.WithValue(context.Background(), ctxKey{}, expectedVal)
+
+		ctx := NewBackgroundContext(childCtx)
+		gotVal, ok := ctx.Value(ctxKey{}).(string)
+		assert.True(t, ok, "expected context to contain a string value for ctxKey")
+		assert.Equal(t, expectedVal, gotVal, "expected value for ctxKey to be %q, got %q", expectedVal, gotVal)
+	})
+	t.Run("background context does not have a deadline", func(t *testing.T) {
+		// Tests the Deadline function.
+
+		childCtx, cancel := context.WithTimeout(context.Background(), time.Second)
+		defer cancel()
+
+		ctx := NewBackgroundContext(childCtx)
+		deadline, ok := ctx.Deadline()
+		assert.False(t, ok, "expected context to have no deadline, but got %v", deadline)
+	})
+	t.Run("background context cannot be cancelled", func(t *testing.T) {
+		// Tests the Done and Err functions.
+
+		childCtx, cancel := context.WithCancel(context.Background())
+		cancel()
+
+		ctx := NewBackgroundContext(childCtx)
+		select {
+		case <-ctx.Done():
+			t.Fatalf("expected context to not expire, but Done channel had a value; ctx error: %v", ctx.Err())
+		default:
+		}
+		assert.Nil(t, ctx.Err(), "expected context error to be nil, got %v", ctx.Err())
+	})
+}