Improve test coverage

test/runtests.jl

@@ -1,37 +1,50 @@
 using Tau
 using Base.Test
 
+# Basic tests
 @test_broken tau == 2*pi
 @test Float32(tau) == 2*Float32(pi)
 @test Float64(Float32(tau)) == Float64(2*Float32(pi))
 @test big(tau) == 2(big(pi))
 @test isa(tau, Irrational)
 
-# degree-based trig functions
+# Test approximate results of degree-based trig functions
 for T = (Float32,Float64)
     for x = -2:0.1:2
         @test_approx_eq_eps sintau(convert(T,x))::T convert(T,sin(tau*x)) eps(tau*convert(T,x))
         @test_approx_eq_eps costau(convert(T,x))::T convert(T,cos(tau*x)) eps(tau*convert(T,x))
     end
-    for x = 0.0:1.0:4.0
-        @test sintau(convert(T,x)) === zero(T)
-        @test sintau(-convert(T,x)) === -zero(T)
+end
+
+# Test exact results of passing integer values to sintau/costau
+for T = (Int, Complex)
+    for x = -3:3
+        @test sintau(convert(T,x)) == zero(T)
+        @test costau(convert(T,x)) == one(T)
     end
 end
 
-# Adapted from julia/test/math.jl
+# Test exact results of passing integer values to sintau/costau as float types
+for T = (Float32, Float64, BigFloat, Complex)
+    for x = -3.0:3.0
+        @test sintau(convert(T,x)) == sign(x)*zero(T)
+        @test costau(convert(T,x)) == one(T)
+    end
+end
 
-# check type stability
-for T = (Float32,Float64,BigFloat)
+# Check type stability of sintau/costau (adapted from julia/test/math.jl)
+for T = (Int,Float32,Float64,BigFloat)
     for f = (sintau,costau)
         @test Base.return_types(f,Tuple{T}) == [T]
     end
 end
 
-# Adapted from julia/test/mod2pi.jl
+# Test passing Inf to sintau / costau
+@test_throws DomainError sintau(Inf)
+@test_throws DomainError costau(Inf)
 
+# Test modtau (adapted from julia/test/mod2pi.jl)
 @test_throws ArgumentError modtau(Int64(2)^60-1)
-
 @test modtau(10) ≈ mod(10, tau)
 @test modtau(-10) ≈ mod(-10, tau)
 @test modtau(355) ≈ 3.1416227979431572