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Specification Test Nonconformity & Notes
Here we document any nonconformity in the specification tests.
Expression:
minimum Decimal
Expected result:
-99999999999999999999.99999999
Actual output:
-79228162514264337593543950335
Rationale:
Per the spec:
Note that if implementations support larger and/or more precise values than the minimum required precision and scale for Decimal, DateTime, and Time values, they will return the minimum representable decimal for the implementation.
Since the SDK uses the C# decimal type to represent the ELM System.Decimal type, we can represent smaller decimals than the minimum required by the specification.
Action:
Test skipped
Recommendation:
Change the expression in the test to be minimum Decimal <= -99999999999999999999.99999999 with an expected output of true
Expression:
maximum Decimal
Expected result:
99999999999999999999.99999999
Actual output:
79228162514264337593543950335
Rationale:
Per the spec:
Note that if implementations support larger and/or more precise values than the minimum required precision and scale for Decimal, DateTime, and Time values, they will return the minimum representable decimal for the implementation.
Since the SDK uses the C# decimal type to represent the ELM System.Decimal type, we can represent larger decimals than the maximum required by the specification.
Action:
Test skipped
Recommendation:
Change the expression in the test to be maximum Decimal >= 99999999999999999999.99999999 with an expected output of true
Expression:
1.0 'cm' * 2.0 'cm'
Expected result:
2.0'cm2'
Actual output:
Rationale:
Unit arithmetic is not yet supported. Quantities used in arithmetic expressions must have the default UCUM unit of 1.
Action:
Test skipped
Expression:
Power(2, -2)
Expected result:
0.25
Actual output:
0
Rationale:
As converted to ELM, the result type of this expression is defined to be System.Integer. Obeying this result type requires that we truncate from 0.25, the mathematically correct result, to 0.
Action:
Test skipped
Recommendation:
The spec discusses behavior for mixed argument types, but does not explicitly state that when Power is used with two Integer arguments that the result type should also be an Integer and decimal portions will be truncated. Given the behavior of the cql-to-elm reference implementation, that behavior is established. This contradicts the expected result of the test. Either the translator has to be updated to match the test, or the test should have an expected outcome of 0. In both cases, the spec should be updated to clarify this.
Expression:
Round(-0.5)
Expected result:
1.0
Actual output:
0
Rationale:
The spec uses the language "traditional round" to describe the rounding method. We use the default rounding strategy which is described in the language as "to nearest." For reference, .NET has devoted significant thought to this here.
This test contradicts the others when using the "to nearest" rounding.
Recommendation:
Clarify the rounding strategy, or fix the expected output of this test.
See Round0D5
See Multiply1CMBy2CM
Expression:
1'cm' ~ 0.01'm'
Expected result:
true
Actual output:
false
Rationale:
Quantity comparison of non-same units is not yet supported. Quantities used in comparison expressions must have the same unit.
Action:
Test skipped
See EquivEqCM1M01
Expression:
years between DateTime(2005) and DateTime(2010)
Expected result:
Interval[4,5]
Actual output:
5
Rationale:
Per the spec:
The result of this operation is always an integer; any fractional periods are dropped.
Action:
Test skipped
Recommendation:
Change the expected output of this test to be 5.