Expect a value within a given range using Google Test

Question

I want to specify an expectation that a value is between an upper and lower bound, inclusively.

Google Test provides LT,LE,GT,GE, but no way of testing a range that I can see. You could use EXPECT_NEAR and juggle the operands, but in many cases this isn't as clear as explicitly setting upper and lower bounds.

Usage should resemble:

EXPECT_WITHIN_INCLUSIVE(1, 3, 2); // 2 is in range [1,3] 

How would one add this expectation?

Answer 1

Google mock has richer composable matchers:

EXPECT_THAT(x, AllOf(Ge(1),Le(3))); 

Maybe that would work for you.

Answer 2

Using just Google Test (not mock), then the simple, obvious answer is:

EXPECT_TRUE((a >= 1) && (a <= 3)); // a is between 1 and 3 inclusive 

I find this more readable than some of the Mock based answers.

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The simple answer above not providing any useful diagnostics

You can use AssertionResult to define a custom assert that does produce useful a useful error message like this.

#include <gtest/gtest.h>  ::testing::AssertionResult IsBetweenInclusive(int val, int a, int b) {     if((val >= a) && (val <= b))         return ::testing::AssertionSuccess();     else         return ::testing::AssertionFailure()                << val << " is outside the range " << a << " to " << b; }  TEST(testing, TestPass) {     auto a = 2;     EXPECT_TRUE(IsBetweenInclusive(a, 1, 3)); }  TEST(testing, TestFail) {     auto a = 5;     EXPECT_TRUE(IsBetweenInclusive(a, 1, 3)); }