CODEWITHSUNDEEP
scalafloating-pointassertscalatest
JoeMjr2
JoeMjr2

Reputation: 3944

Comparing floating point numbers with tolerance fails assertion

I am using ScalaTest (3.0.4), and can't get any examples to work that I've found of comparing floating point numbers with a tolerance. Here's what I have:

import org.scalatest.{MustMatchers, WordSpec}

class DetectionClusteringSpec extends WordSpec with MustMatchers {

    "EmbeddingsGroup.vecdist" should {
        "correctly compute vector distance" in {
            val dist = EmbeddingsGroup.vecdist(TestDetections.emb1,TestDetections.emb4)
            // Note: The above method returns a Float. 

            dist mustBe 3.058 +- 0.1
        }
    }

The above compiles, but when I run the test, I get the following failure:

3.0579379 was not equal to 3.058 +- 0.1
Expected :3.058 +- 0.1
Actual   :3.0579379

I also tied the following assertion instead: 

assert(dist === 3.058)

However, that does not work either, and gives the following failure:

3.0579379 did not equal 3.058
Expected :3.058
Actual   :3.0579379

I've read numerous examples of comparing floating point numbers with both of the above syntaxes, and it seems like they should work. My first example is straight from the documentation.

What am I doing wrong?

Upvotes: 1

Views: 696

Answers (1)

Mario Galic
Mario Galic

Reputation: 48410

Since dist is a Float whilst other arguments are Doubles try converting dist to Double like so

dist.toDouble mustBe 3.058D +- 0.1

or make other arguments floats like so

dist mustBe 3.058f +- 0.1f

Possibly related to Comparison matchers fail on mixed numeric types

Upvotes: 1

Related Questions