diff --git a/R/highlevel64.R b/R/highlevel64.R
index 6096b71..319d087 100644
--- a/R/highlevel64.R
+++ b/R/highlevel64.R
@@ -2999,11 +2999,13 @@ quantile.integer64 <- function(x, probs = seq(0.0, 1.0, 0.25), na.rm = FALSE, na
 # TODO(R>=3.4.0): Drop this branch when median always gets '...'
 # adding ... (wish of Kurt Hornik 23.3.2017)
 if (is.na(match("...", names(formals(median))))){
+    # nocov start. Only run on old R.
     median.integer64 <- function(x, na.rm=FALSE){
         if (!na.rm && na.count(x)>0L)
             stop("missing values not allowed with 'na.rm='==FALSE")
         qtile.integer64(x, probs = 0.5, na.rm = na.rm, names = FALSE)
     }
+    # nocov end.
 }else{
     median.integer64 <- function(x, na.rm=FALSE, ...){
         if (!na.rm && na.count(x)>0L)
diff --git a/tests/testthat/test-highlevel64.R b/tests/testthat/test-highlevel64.R
index 286e971..f4b8739 100644
--- a/tests/testthat/test-highlevel64.R
+++ b/tests/testthat/test-highlevel64.R
@@ -1,4 +1,4 @@
-test_that("match basics work", {
+test_that("match & %in% basics work", {
   x = as.integer64(2:5)
   y = as.integer64(3:6)
   expect_identical(match(x, y), c(NA, 1:3))
@@ -10,4 +10,49 @@ test_that("match basics work", {
   expect_identical(match(y, as.numeric(2:5)), c(2:4, NA))
 
   expect_identical(match(x, y, nomatch=0L), 0:3)
+
+  expect_identical(x %in% y, c(FALSE, TRUE, TRUE, TRUE))
+  expect_identical(y %in% x, c(TRUE, TRUE, TRUE, FALSE))
+  expect_identical(x %in% 3:6, c(FALSE, TRUE, TRUE, TRUE))
+  expect_identical(x %in% c(3.0, 4.0, 5.0, 6.0), c(FALSE, TRUE, TRUE, TRUE))
+})
+
+test_that("duplicated, unique, table methods work", {
+  x = as.integer64(1:3)
+  expect_identical(duplicated(x), rep(FALSE, 3L))
+  expect_identical(unique(x), x)
+  expect_identical(table(x), table(x = 1:3))
+
+  x = as.integer64(rep(1L, 3L))
+  expect_identical(duplicated(x), c(FALSE, TRUE, TRUE))
+  expect_identical(unique(x), x[1L])
+  expect_identical(table(x), table(x = rep(1L, 3L)))
+
+  x = as.integer64(c(1L, 2L, 1L))
+  expect_identical(duplicated(x), c(FALSE, FALSE, TRUE))
+  expect_identical(unique(x), x[1:2])
+  expect_identical(table(x), table(x = c(1L, 2L, 1L)))
+
+  x = as.integer64(c(1L, 1L, 2L))
+  expect_identical(duplicated(x), c(FALSE, TRUE, FALSE))
+  expect_identical(unique(x), x[c(1L, 3L)])
+  expect_identical(table(x), table(x = c(1L, 1L, 2L)))
+})
+
+test_that("more coercion works", {
+  expect_identical(as.factor(as.integer64(2:4)), factor(2:4))
+  expect_identical(as.ordered(as.integer64(2:4)), as.ordered(2:4))
+  expect_identical(as.integer64(factor(2:11)), as.integer64(1:10)) # NB: _not_ 2:11!
+})
+
+test_that("sorting methods work", {
+  expect_identical(rank(as.integer64(c(10L, 4L, 8L))), c(3.0, 1.0, 2.0))
+
+  x = as.integer64(1:100)
+  q = as.integer64(c(1L, 26L, 50L, 75L, 100L))
+  expect_identical(quantile(x, names=FALSE), q)
+  expect_identical(median(x), q[3L])
+  names(q) = c('0%', '25%', '50%', '75%', '100%')
+  expect_identical(quantile(x), q)
+  expect_identical(quantile(x, 0.2, names=FALSE), as.integer64(21L))
 })
diff --git a/tests/testthat/test-integer64.R b/tests/testthat/test-integer64.R
index 4b00e63..bd6572b 100644
--- a/tests/testthat/test-integer64.R
+++ b/tests/testthat/test-integer64.R
@@ -9,7 +9,6 @@ test_that("integer64 coercion to/from other types work", {
   # to integer64
   expect_identical(as.integer64(TRUE), as.integer64(1L))
   expect_identical(as.integer64(as.character(1:10)), as.integer64(1:10))
-  expect_identical(as.integer64(factor(2:11)), as.integer64(1:10)) # NB: _not_ 2:11!
   expect_identical(as.integer64(as.double(1:10)), as.integer64(1:10))
   expect_identical(as.integer64(NULL), as.integer64())
   x = as.integer64(1:10)