Fix integrate for several variables and add simple tests (#149)

src/calculus.jl

@@ -298,10 +298,10 @@ function integrate(a::HomogeneousPolynomial, r::Int)
     a.order == order_max && return HomogeneousPolynomial(zero(T), 0)
 
     @inbounds posTb = pos_table[a.order+2]
-    @inbounds num_coeffs = size_table[a.order+2]
-    coeffs = zeros(T, size_table[num_coeffs])
     @inbounds num_coeffs = size_table[a.order+1]
 
+    coeffs = zeros(T, size_table[a.order+2])
+
     @inbounds for i = 1:num_coeffs
         iind = coeff_table[a.order+1][i]
         n = iind[r]

test/manyvariables.jl

@@ -159,6 +159,9 @@ end
     @test integrate(xT^17, 1, 2.0) == 2.0
     @test_throws AssertionError integrate(xT, 1, xT)
 
+
+
+
     @test derivative(2xT*yT^2,1) == 2yT^2
     @test xT*xT^3 == xT^4
     txy = 1.0 + xT*yT - 0.5*xT^2*yT + (1/3)*xT^3*yT + 0.5*xT^2*yT^2
@@ -545,3 +548,16 @@ end
     TaylorSeries.rad2deg!(yT, xT, 0)
     @test yT[0] == xT[0]*(180/pi)
 end
+
+@testset "Integrate for several variables" begin
+
+    t, x, y = set_variables("t x y")
+
+    @test integrate(t, 1) == 0.5*t^2
+    @test integrate(t, 2) == t * x
+    @test integrate(t, 3) == t * y
+    @test integrate(x, 1) == t * x
+    @test integrate(x, 2) == 0.5*x^2
+    @test integrate(y, 2) == x * y
+
+end