Even though decimal digit are correct, assert are getting failed - nunit

Question

I have those 2 values :
Expected Value (fResult)= 103393.431493782901937514
Actual Value (output) = 103393.431493782901937514
When I assert on the value, my expected result was consider as 103393.431493783m
Because of that my Assert was fails. Can anyone help in this regard.
Assert.That(output, Is.EqualTo(fResult));
More Information: both Actual and Expected values are Decimal data type,
[TestCase("value1", "value2", 5, 103393.431493782901937514)]
public void converFormulaforPressure(String Fromunit, String toUnit, decimal Avalue, decimal fResult) {
var output = ut1.Convert(ut1.GetUnit("Pressure", Fromunit), ut1.GetUnit("Pressure", toUnit), Avalue).Val;
Assert.That(output, Is.EqualTo(fResult));
}
ut1.Convert is a method which converts the value and give the Actual result .

Answer 1

You need to provide a tolerance level and you cannot pass a decimal as a TestCase parameter. The code you provided is passing the last value as a double, hence the rounding when you run the assert. You can solve this by using TestCaseSource instead.
The test below passes:
private static readonly object[] TestCases = {
new object[] {"value1", "value2", 5m, 103393.431493782901937514m}
};
[Test, TestCaseSource("TestCases")]
public void TestExample(string fromUnit, string toUnit, decimal value, decimal fResult) {
//Replace the line below with your convert method using values from testCase
var output = 103393.431493782901937514m;
Assert.That(output, Is.EqualTo(fResult).Within(0.00000000000001));
}