diff --git a/tests/testthat/test-matrix.R b/tests/testthat/test-matrix.R
index 4106c6d..40c0478 100644
--- a/tests/testthat/test-matrix.R
+++ b/tests/testthat/test-matrix.R
@@ -1,3 +1,79 @@
+test_that("%*%", {
+  # mat %*% mat
+  mat_x <- matrix(1:9, 3,
+                  dimnames = list(axis1 = 1:3,
+                                  axis2 = 1:3))
+  mat_y <- matrix(1:9, 3,
+                  dimnames = list(axis2 = 1:3,
+                                  axis3 = 1:3))
+  ddf_x <- as_dibble(mat_x)
+  ddf_y <- as_dibble(mat_y)
+  expect_equal(as.matrix(ddf_x %*% ddf_y), unname(mat_x %*% mat_y))
+
+  mat_x <- matrix(1:9, 3,
+                  dimnames = list(axis2 = 1:3,
+                                  axis1 = 1:3))
+  mat_y <- matrix(1:9, 3,
+                  dimnames = list(axis2 = 1:3,
+                                  axis3 = 1:3))
+  ddf_x <- as_dibble(mat_x)
+  ddf_y <- as_dibble(mat_y)
+  expect_equal(as.matrix(ddf_x %*% ddf_y), unname(t(mat_x) %*% mat_y))
+
+  # vec %*% mat
+  vec_x <- array(1:3, 3,
+                 dimnames = list(axis2 = 1:3))
+  mat_y <- matrix(1:9, 3,
+                  dimnames = list(axis2 = 1:3,
+                                  axis3 = 1:3))
+  ddf_x <- as_dibble(vec_x)
+  ddf_y <- as_dibble(mat_y)
+  expect_equal(as.matrix(ddf_x %*% ddf_y), t(unname(vec_x %*% mat_y)))
+
+  vec_x <- array(1:3, 3,
+                 dimnames = list(axis2 = 1:3))
+  mat_y <- matrix(1:9, 3,
+                  dimnames = list(axis3 = 1:3,
+                                  axis2 = 1:3))
+  ddf_x <- as_dibble(vec_x)
+  ddf_y <- as_dibble(mat_y)
+  expect_equal(as.matrix(ddf_x %*% ddf_y), t(unname(vec_x %*% t(mat_y))))
+
+  # mat %*% vec
+  mat_x <- matrix(1:9, 3,
+                  dimnames = list(axis1 = 1:3,
+                                  axis2 = 1:3))
+  vec_y <- array(1:3, 3,
+                 dimnames = list(axis2 = 1:3))
+  ddf_x <- as_dibble(mat_x)
+  ddf_y <- as_dibble(vec_y)
+  expect_equal(as.matrix(ddf_x %*% ddf_y), unname(mat_x %*% vec_y))
+
+  mat_x <- matrix(1:9, 3,
+                  dimnames = list(axis2 = 1:3,
+                                  axis1 = 1:3))
+  vec_y <- array(1:3, 3,
+                 dimnames = list(axis2 = 1:3))
+  ddf_x <- as_dibble(mat_x)
+  ddf_y <- as_dibble(vec_y)
+  expect_equal(as.matrix(ddf_x %*% ddf_y), unname(t(mat_x) %*% vec_y))
+})
+
+test_that("t", {
+  # vec
+  vec <- array(1:3, 3,
+               dimnames = list(axis = 1:3))
+  ddf <- as_dibble(vec)
+  expect_equal(as.array(t(ddf)), unname(t(vec)))
+
+  # mat
+  mat <- matrix(1:9, 3,
+                dimnames = list(axis1 = 1:3,
+                                axis2 = 1:3))
+  ddf <- as_dibble(mat)
+  expect_equal(as.array(t(ddf)), unname(t(mat)))
+})
+
 test_that("diag", {
   arr <- matrix(1:9, 3)
   ddf_col <- broadcast(1:9,