fix off by one in csc_premute and add test

Author: KristofferC

base/sparse/csparse.jl

@@ -269,7 +269,7 @@ function csc_permute{Tv,Ti}(A::SparseMatrixCSC{Tv,Ti}, pinv::Vector{Ti}, q::Vect
     end
     if !isperm(pinv) || !isperm(q) error("both pinv and q must be permutations") end
     C = copy(A); Cp = C.colptr; Ci = C.rowval; Cx = C.nzval
-    nz = zero(Ti)
+    nz = one(Ti)
     for k in 1:n
         Cp[k] = nz
         j = q[k]

test/sparsedir/sparse.jl

@@ -909,7 +909,6 @@ A = sparse(ones(5,5))
 @test_throws DimensionMismatch one(sprand(5,6,0.2))
 
 #istriu/istril
-
 A = sparse(triu(rand(5,5)))
 @test istriu(A)
 @test !istriu(sparse(ones(5,5)))
@@ -918,29 +917,36 @@ A = sparse(tril(rand(5,5)))
 @test !istril(sparse(ones(5,5)))
 
 # symperm
-
 srand(1234321)
 A = triu(sprand(10,10,0.2))       # symperm operates on upper triangle
 perm = randperm(10)
 @test symperm(A,perm).colptr == [1,2,3,3,3,4,5,5,7,9,10]
 
-# droptol
+#csc_permute
+A = sprand(10,10,0.2)
+pinv = randperm(10)
+p = zeros(Int, 10)
+# Invert pinv
+for (i, j) in enumerate(pinv)
+    p[j] = i
+end
+q = randperm(10)
+@test csc_permute(A, pinv, q) == full(A)[p, q]
 
+# droptol
 @test Base.droptol!(A,0.01).colptr == [1,1,1,2,2,3,4,6,6,7,9]
+@test Base.droptol(A,0.01).colptr == [1,1,1,2,2,3,4,6,6,7,9]
 
 #trace
-
 @test_throws DimensionMismatch trace(sparse(ones(5,6)))
 @test trace(speye(5)) == 5
 
 #diagm on a matrix
-
 @test_throws DimensionMismatch diagm(sparse(ones(5,2)))
 @test_throws DimensionMismatch diagm(sparse(ones(2,5)))
 @test diagm(sparse(ones(1,5))) == speye(5)
 
 # triu/tril
-
 A = sprand(5,5,0.2)
 AF = full(A)
 @test full(triu(A,1)) == triu(AF,1)