Assert equals doubles

munit/shared/src/main/scala/munit/Assertions.scala

@@ -67,7 +67,7 @@ trait Assertions extends MacroCompat.CompileErrorMacro {
   )(implicit loc: Location, ev: A =:= B): Unit = {
     StackTraces.dropInside {
       if (obtained == expected) {
-        fail(munitPrint(clue))
+        fail(s"${munitPrint(clue)} expected same: $expected was not: $obtained")
       }
     }
   }
@@ -120,6 +120,40 @@ trait Assertions extends MacroCompat.CompileErrorMacro {
     }
   }
 
+  /**
+   * Asserts that two doubles or floats are equal to within a positive delta.
+   * If the expected value is infinity then the delta value is ignored.
+   * NaNs are considered equal: assertEquals(Double.NaN, Double.NaN, *) passes.
+   */
+  def assertEquals(
+      obtained: Double,
+      expected: Double,
+      delta: Double
+  )(implicit loc: Location): Unit = {
+    val defaultClue = "values are not the same"
+    assertEquals(obtained, expected, delta, defaultClue)
+  }
+
+  /**
+   * Asserts that two doubles or floats are equal to within a positive delta.
+   * If the expected value is infinity then the delta value is ignored.
+   * NaNs are considered equal: assertEquals(Double.NaN, Double.NaN, *, *) passes.
+   */
+  def assertEquals(
+      obtained: Double,
+      expected: Double,
+      delta: Double,
+      clue: => Any
+  )(implicit loc: Location): Unit = {
+    StackTraces.dropInside {
+      val exactlyTheSame = java.lang.Double.compare(expected, obtained) == 0
+      val almostTheSame = Math.abs(expected - obtained) <= delta
+      if (!exactlyTheSame && !almostTheSame) {
+        fail(s"${munitPrint(clue)} expected: $expected but was: $obtained")
+      }
+    }
+  }
+
   def intercept[T <: Throwable](
       body: => Any
   )(implicit T: ClassTag[T], loc: Location): T = {

tests/shared/src/test/scala/munit/DoubleAssertionsFrameworkSuite.scala

@@ -0,0 +1,98 @@
+package munit
+
+class DoubleAssertionsFrameworkSuite extends BaseSuite {
+  test("Assert Equals NaN Fails".fail) {
+    assertEquals(1.234, Double.NaN, 0.0)
+  }
+
+  test("Assert NaN Equals Fails".fail) {
+    assertEquals(Double.NaN, 1.234, 0.0)
+  }
+
+  test("Assert NaN Equals NaN") {
+    assertEquals(Double.NaN, Double.NaN, 0.0)
+  }
+
+  test("Assert Pos Infinity Not Equals Neg Infinity".fail) {
+    assertEquals(Double.PositiveInfinity, Double.NegativeInfinity, 0.0)
+  }
+
+  test("Assert Pos Infinity Not Equals".fail) {
+    assertEquals(Double.PositiveInfinity, 1.23, 0.0)
+  }
+
+  test("Assert Pos Infinity Equals Infinity") {
+    assertEquals(Double.PositiveInfinity, Double.PositiveInfinity, 0.0)
+  }
+
+  test("Assert Neg Infinity Equals Infinity") {
+    assertEquals(Double.NegativeInfinity, Double.NegativeInfinity, 0.0)
+  }
+
+  test("All Infinities") {
+    assertEquals(
+      Double.PositiveInfinity,
+      Double.NegativeInfinity,
+      Double.PositiveInfinity
+    )
+  }
+
+  // And now, the same with floats...
+  test("Assert Equals NaN Fails".fail) {
+    assertEquals(1.234f, Float.NaN, 0.0)
+  }
+
+  test("Assert NaN Equals Fails".fail) {
+    assertEquals(Float.NaN, 1.234f, 0.0)
+  }
+
+  test("Assert NaN Equals NaN") {
+    assertEquals(Float.NaN, Float.NaN, 0.0)
+  }
+
+  test("Assert Pos Infinity Not Equals Neg Infinity".fail) {
+    assertEquals(Float.PositiveInfinity, Float.NegativeInfinity, 0.0)
+  }
+
+  test("Assert Pos Infinity Not Equals".fail) {
+    assertEquals(Float.PositiveInfinity, 1.23f, 0.0)
+  }
+
+  test("Assert Pos Infinity Equals Infinity") {
+    assertEquals(Float.PositiveInfinity, Float.PositiveInfinity, 0.0)
+  }
+
+  test("Assert Neg Infinity Equals Infinity") {
+    assertEquals(Float.NegativeInfinity, Float.NegativeInfinity, 0.0)
+  }
+
+  test("All Infinities") {
+    assertEquals(
+      Float.PositiveInfinity,
+      Float.NegativeInfinity,
+      Float.PositiveInfinity
+    )
+  }
+}
+
+object DoubleAssertionsFrameworkSuite
+    extends FrameworkTest(
+      classOf[DoubleAssertionsFrameworkSuite],
+      """|==> success munit.DoubleAssertionsFrameworkSuite.Assert Equals NaN Fails
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert NaN Equals Fails
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert NaN Equals NaN
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert Pos Infinity Not Equals Neg Infinity
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert Pos Infinity Not Equals
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert Pos Infinity Equals Infinity
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert Neg Infinity Equals Infinity
+         |==> success munit.DoubleAssertionsFrameworkSuite.All Infinities
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert Equals NaN Fails-1
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert NaN Equals Fails-1
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert NaN Equals NaN-1
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert Pos Infinity Not Equals Neg Infinity-1
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert Pos Infinity Not Equals-1
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert Pos Infinity Equals Infinity-1
+         |==> success munit.DoubleAssertionsFrameworkSuite.Assert Neg Infinity Equals Infinity-1
+         |==> success munit.DoubleAssertionsFrameworkSuite.All Infinities-1
+         |""".stripMargin
+    )

tests/shared/src/test/scala/munit/FrameworkSuite.scala

@@ -27,6 +27,7 @@ class FrameworkSuite extends BaseFrameworkSuite {
     FullStackTraceFrameworkSuite,
     SmallStackTraceFrameworkSuite,
     AssertionsFrameworkSuite,
+    DoubleAssertionsFrameworkSuite,
     ScalaCheckExceptionFrameworkSuite
   )
   tests.foreach { t => check(t) }