diff --git a/README.md b/README.md
index 733348c..a209e0d 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ code = create_basis(
      (0.5, 0.0, 0.5), # N9
      (0.0, 0.5, 0.5), # N10
     ),
-    "1 + u + v + w + u*v + v*w + w*u + u^2 + v^2 + w^2",
+    :(1 + u + v + w + u*v + v*w + w*u + u^2 + v^2 + w^2),
    )
 ```
 
@@ -114,11 +114,11 @@ code = create_basis(
      ( 0.0,  0.0,  1.0), # N5
     ),
     (
-     "1/8 * (1-u) * (1-v) * (1-w)",
-     "1/8 * (1+u) * (1-v) * (1-w)",
-     "1/8 * (1+u) * (1+v) * (1-w)",
-     "1/8 * (1-u) * (1+v) * (1-w)",
-     "1/2 * (1+w)",
+     :(1/8 * (1-u) * (1-v) * (1-w)),
+     :(1/8 * (1+u) * (1-v) * (1-w)),
+     :(1/8 * (1+u) * (1+v) * (1-w)),
+     :(1/8 * (1-u) * (1+v) * (1-w)),
+     :(1/2 * (1+w)),
     ),
    )
 eval(code)
diff --git a/src/create_basis.jl b/src/create_basis.jl
index 895bc5b..245c0a1 100644
--- a/src/create_basis.jl
+++ b/src/create_basis.jl
@@ -85,7 +85,7 @@ end
 """
 Calculate derivatives of basis functions with respect to parameters u, v, w.
 """
-function calculate_interpolation_polynomial_derivatives(basis::Vector, dim::Int)
+function calculate_interpolation_polynomial_derivatives(basis, dim)
     equations = Vector[]
     vars = [:u, :v, :w]
     nbasis = length(basis)
@@ -101,7 +101,7 @@ function calculate_interpolation_polynomial_derivatives(basis::Vector, dim::Int)
     return equations
 end
 
-function create_basis{nbasis,dim}(name::Symbol, description::String, X::NTuple{nbasis, NTuple{dim, Float64}}, basis::Vector, dbasis::Vector)
+function create_basis{nbasis,dim}(name::Symbol, description::String, X::NTuple{nbasis, NTuple{dim, Float64}}, basis, dbasis)
 
     Q = Expr(:block)
     for i=1:nbasis
@@ -177,3 +177,8 @@ function create_basis{nbasis,dim}(name::Symbol, description::String, X::NTuple{n
     dbasis = calculate_interpolation_polynomial_derivatives(basis, dim)
     return create_basis(name, description, X, basis, dbasis)
 end
+
+function create_basis{nbasis,dim}(name::Symbol, description::String, X::NTuple{nbasis, NTuple{dim, Float64}}, basis::NTuple{nbasis, Expr})
+    dbasis = calculate_interpolation_polynomial_derivatives(basis, dim)
+    return create_basis(name, description, X, basis, dbasis)
+end
diff --git a/test/test_create_basis.jl b/test/test_create_basis.jl
index 0060738..2936bdb 100644
--- a/test/test_create_basis.jl
+++ b/test/test_create_basis.jl
@@ -6,6 +6,8 @@ using FEMBasis
 #using FEMBasis: calculate_basis_coefficients, calculate_interpolation_polynomials,
 #                calculate_interpolation_polynomial_derivatives, create_lagrange_basis
 
+@testset "FEMBasis.jl" begin
+
 @testset "Calculate interpolation polynomial matrix" begin
     p = :(1 + u + v)
     X = ((0.0, 0.0), (1.0, 0.0), (0.0, 1.0))
@@ -18,9 +20,6 @@ end
     p = :(1 + u + v)
     A = [1.0 0.0 0.0; 1.0 1.0 0.0; 1.0 0.0 1.0]
     equations = FEMBasis.calculate_interpolation_polynomials(p, A)
-    for j=1:3
-        println(equations[j])
-    end
     @test equations[1] == :(1.0 + -u + -v)
     @test equations[2] == :(+u)
     @test equations[3] == :(+v)
@@ -28,7 +27,6 @@ end
 
 
 @testset "Calculate derivatives of interpolation polynomials" begin
-    println("call derivatve function")
     basis = [:(1.0 - u - v), :(1.0u), :(1.0v)]
     dbasis = FEMBasis.calculate_interpolation_polynomial_derivatives(basis, 2)
     @test isapprox(dbasis[1][1], -1.0)
@@ -44,7 +42,6 @@ end
     basis = [:(1.0 - u - v), :(1.0u), :(1.0v)]
     dbasis = Vector[[-1.0, -1.0], [1.0, 0.0], [0.0, 1.0]]
     code = FEMBasis.create_basis(:TestTriangle, "test triangle", X, basis, dbasis)
-    println(code)
     eval(code)
     N = zeros(1,size(TestTriangle, 2))
     X = get_reference_element_coordinates(TestTriangle)
@@ -63,12 +60,10 @@ end
     @test isapprox(dN, [-1.0 1.0 0.0; -1.0 0.0 1.0])
 end
 
-@testset "test create basis, ansatz polynomial given" begin
+@testset "test create basis, N given" begin
     X = ((0.0, 0.0), (1.0, 0.0), (0.0, 1.0))
-    # p = :(1 + u + v)
-    p = "1 + u + v"
-    code = FEMBasis.create_basis(:TestTriangle, "test triangle", X, p)
-    println(code)
+    basis = ( :(1 - u - v), :(1.0u), :(1.0v) )
+    code = FEMBasis.create_basis(:TestTriangle, "test triangle", X, basis)
     eval(code)
     N = zeros(1,size(TestTriangle, 2))
     X = get_reference_element_coordinates(TestTriangle)
@@ -86,3 +81,30 @@ end
     eval_dbasis!(TestTriangle, dN, X[3])
     @test isapprox(dN, [-1.0 1.0 0.0; -1.0 0.0 1.0])
 end
+
+@testset "test create basis, ansatz polynomial given" begin
+    X = ((0.0, 0.0), (1.0, 0.0), (0.0, 1.0))
+    p1 = :(1 + u + v)
+    p2 = "1 + u + v"
+    code1 = FEMBasis.create_basis(:TestTriangle, "test triangle", X, p1)
+    code2 = FEMBasis.create_basis(:TestTriangle, "test triangle", X, p2)
+    @test code1 == code2
+    eval(code1)
+    N = zeros(1,size(TestTriangle, 2))
+    X = get_reference_element_coordinates(TestTriangle)
+    for i=1:length(TestTriangle)
+        eval_basis!(TestTriangle, N, X[i])
+        N_expected = zeros(1, length(TestTriangle))
+        N_expected[i] = 1.0
+        @test isapprox(N, N_expected)
+    end
+    dN = zeros(size(TestTriangle)...)
+    eval_dbasis!(TestTriangle, dN, X[1])
+    @test isapprox(dN, [-1.0 1.0 0.0; -1.0 0.0 1.0])
+    eval_dbasis!(TestTriangle, dN, X[2])
+    @test isapprox(dN, [-1.0 1.0 0.0; -1.0 0.0 1.0])
+    eval_dbasis!(TestTriangle, dN, X[3])
+    @test isapprox(dN, [-1.0 1.0 0.0; -1.0 0.0 1.0])
+end
+
+end