more tests. comments

Author: vpuri3

test/func.jl

@@ -105,26 +105,28 @@ end
 
     A = Diagonal(p * t)
 
+    # test that output isn't accidentally mutated by passing an internal cache.
+
     u1 = rand(N, K)
     u2 = rand(N, K)
 
-    v1 = L * u1
-    v2 = L * u2
+    v1 = L * u1; @test v1 ≈ A * u1
+    v2 = L * u2; @test v2 ≈ A * u2; @test v1 ≈ A * u1
     @test v1 + v2 ≈ A * (u1 + u2)
 
     v1 .= 0.0
     v2 .= 0.0
 
-    mul!(v1, L, u1)
-    mul!(v2, L, u2)
+    mul!(v1, L, u1); @test v1 ≈ A * u1
+    mul!(v2, L, u2); @test v2 ≈ A * u2; @test v1 ≈ A * u1
     @test v1 + v2 ≈ A * (u1 + u2)
 
     v1 = rand(N, K); w1 = copy(v1)
     v2 = rand(N, K); w2 = copy(v2)
     a1, a2, b1, b2 = rand(4)
 
-    mul!(v1, L, u1, a1, b1)
-    mul!(v2, L, u2, a2, b2)
+    mul!(v1, L, u1, a1, b1); @test v1 ≈ a1*A*u1 + b1*w1
+    mul!(v2, L, u2, a2, b2); @test v2 ≈ a2*A*u2 + b2*w2; @test v1 ≈ a1*A*u1 + b1*w1
     @test v1 + v2 ≈ (a1*A*u1 + b1*w1) + (a2*A*u2 + b2*w2)
 end
 #