Add numbers tests

enso-org · Apr 11, 2022 · f627191 · f627191
1 parent 330b40e
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Showing 2 changed files with 38 additions and 8 deletions.
diff --git a/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Number/Extensions.enso b/distribution/lib/Standard/Base/0.0.0-dev/src/Data/Number/Extensions.enso
@@ -302,3 +302,23 @@ Parse_Error.to_display_text : Text
 Parse_Error.to_display_text =
     "Could not parse " + this.text.to_text + " as a double."
 
+## A constant holding the floating-point positive infinity.
+Number.positive_infinity : Decimal
+Number.positive_infinity = Double.POSITIVE_INFINITY
+
+## A constant holding the floating-point negative infinity.
+Number.negative_infinity : Decimal
+Number.negative_infinity = Double.NEGATIVE_INFINITY
+
+## A constant holding the floating-point Not-a-Number value.
+Number.nan : Decimal
+Number.nan = Double.NaN
+
+## Checks if the given number is the floating-point Not-a-Number value.
+
+   This is needed, because the NaN value will return `False` even when being
+   compared with itself, so `x == Number.nan` would not work.
+Number.is_nan : Boolean
+Number.is_nan = case this of
+    Decimal -> Double.isNaN this
+    _ -> False
diff --git a/test/Tests/src/Data/Numbers_Spec.enso b/test/Tests/src/Data/Numbers_Spec.enso
@@ -262,22 +262,32 @@ spec =
             almost_max_long_times_three_decimal.ceil.to_decimal . should_equal almost_max_long_times_three_plus_1.to_decimal
             almost_max_long_times_three_plus_1.ceil . should_equal almost_max_long_times_three_plus_1
 
+        Test.specify "should expose a NaN value" <|
+            Number.nan.is_nan . should_be_true
+            0.is_nan . should_be_false
+            Number.positive_infinity.is_nan . should_be_false
+            Number.negative_infinity.is_nan . should_be_false
+
+            Number.nan==Number.nan . should_be_false
+            Number.nan==0 . should_be_false
+            Number.nan!=Number.nan . should_be_true
+
         Test.specify "should support inexact equality comparisons" <|
             1.0001 . equals 1.0002 epsilon=0.01 . should_be_true
             1.0001 . equals 1.0002 epsilon=0.0000001 . should_be_false
 
             1 . equals 2 . should_be_false
             1 . equals (0+1) . should_be_true
 
-            inf = 1/0
-            inf . equals inf . should_be_true
+            Number.positive_infinity . equals Number.positive_infinity . should_be_true
+
+            Number.negative_infinity . equals Number.negative_infinity . should_be_true
+            Number.negative_infinity . equals Number.positive_infinity . should_be_false
 
-            neg_inf = -inf
-            neg_inf . equals neg_inf . should_be_true
-            neg_inf . equals inf . should_be_false
+            Number.negative_infinity . should_equal (-Number.positive_infinity)
+            Number.negative_infinity . equals (-Number.positive_infinity) . should_be_true
 
-            nan = 0.log 0
-            nan . equals nan . should_be_false
-            nan . equals 0 . should_be_false
+            Number.nan . equals Number.nan . should_be_false
+            Number.nan . equals 0 . should_be_false
 
 main = Test.Suite.run_main here.spec