attempt to fix test regression in older julia versions

src/WignerSymbols.jl

@@ -286,7 +286,7 @@ function _wigner9j(T::Type{<:Real}, j₁::HalfInteger, j₂::HalfInteger, j₃::
         return m * _convert(T, s) * convert(T, signedroot(r))
     end
 
-    # canonicalized entries
+    # canonicalized entries (m is a restoring sign factor)
     j₁c, j₂c, j₃c, j₄c, j₅c, j₆c, j₇c, j₈c, j₉c = k
 
     # order irrelevant: product remains the same

test/runtests.jl

@@ -216,7 +216,7 @@ end
             js = rand(smalljlist, 9)
 
             debug |= !(@test(wigner9j(js...) ≈ sum(largejlist) do x # lazy choice for range of this sum, but good enough
-                                                (iseven(2x) ? (2x + 1) : -(2x + 1)) *
+                                                (iseven(Int(2x)) ? (2x + 1) : -(2x + 1)) *
                                                     wigner6j(js[1], js[4], js[7],
                                                         js[8], js[9], x ) *
                                                     wigner6j(js[2], js[5], js[8],