diff --git a/DESCRIPTION b/DESCRIPTION
index a85039ce..fb36680a 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -28,7 +28,7 @@ Imports:
     methods
 Suggests:
     covr,
-    ggplot2,
+    ggplot2 (>= 3.3.6),
     lattice,
     rlang,
     testthat (>= 3.0.0),
@@ -37,4 +37,4 @@ Config/Needs/website: tidyverse/tidytemplate
 Config/testthat/edition: 3
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE)
-RoxygenNote: 7.2.3
+RoxygenNote: 7.3.1
diff --git a/R/replay.R b/R/replay.R
index d0b16c2e..3175a91c 100644
--- a/R/replay.R
+++ b/R/replay.R
@@ -6,12 +6,22 @@
 #' @param x result from [evaluate()]
 #' @export
 #' @examples
-#' samples <- system.file("tests", "testthat", package = "evaluate")
-#' if (file_test("-d", samples)) {
-#'   replay(evaluate(file(file.path(samples, "order.R"))))
-#'   replay(evaluate(file(file.path(samples, "plot.R"))))
-#'   replay(evaluate(file(file.path(samples, "data.R"))))
+#' f1 <- function() {
+#'   cat("1\n")
+#'   print("2")
+#'   warning("3")
+#'   print("4")
+#'   message("5")
+#'   stop("6")
 #' }
+#' replay(evaluate("f1()"))
+#' 
+#' f2 <- function() {
+#'   message("Hello")
+#'   plot(1:10)
+#'   message("Goodbye")
+#' }
+#' replay(evaluate("f2()"))
 replay <- function(x) UseMethod("replay", x)
 
 #' @export
diff --git a/man/replay.Rd b/man/replay.Rd
index b9f18b21..4ddbdf01 100644
--- a/man/replay.Rd
+++ b/man/replay.Rd
@@ -14,10 +14,20 @@ Replay a list of evaluated results, as if you'd run them in an R
 terminal.
 }
 \examples{
-samples <- system.file("tests", "testthat", package = "evaluate")
-if (file_test("-d", samples)) {
-  replay(evaluate(file(file.path(samples, "order.R"))))
-  replay(evaluate(file(file.path(samples, "plot.R"))))
-  replay(evaluate(file(file.path(samples, "data.R"))))
+f1 <- function() {
+  cat("1\n")
+  print("2")
+  warning("3")
+  print("4")
+  message("5")
+  stop("6")
 }
+replay(evaluate("f1()"))
+
+f2 <- function() {
+  message("Hello")
+  plot(1:10)
+  message("Goodbye")
+}
+replay(evaluate("f2()"))
 }
diff --git a/tests/testthat/_snaps/errors.md b/tests/testthat/_snaps/errors.md
new file mode 100644
index 00000000..0a97eddb
--- /dev/null
+++ b/tests/testthat/_snaps/errors.md
@@ -0,0 +1,8 @@
+# code errors if stop_on_error == 2L
+
+    Code
+      evaluate("stop(\"1\")", stop_on_error = 2L)
+    Condition
+      Error:
+      ! 1
+
diff --git a/tests/testthat/comment.R b/tests/testthat/comment.R
deleted file mode 100644
index ca63e33f..00000000
--- a/tests/testthat/comment.R
+++ /dev/null
@@ -1,2 +0,0 @@
-# This test case contains no executable code
-# but it shouldn't throw an error
diff --git a/tests/testthat/data.R b/tests/testthat/data.R
deleted file mode 100644
index fd772172..00000000
--- a/tests/testthat/data.R
+++ /dev/null
@@ -1,2 +0,0 @@
-data(barley, package = "lattice")
-barley
diff --git a/tests/testthat/error-complex.R b/tests/testthat/error-complex.R
deleted file mode 100644
index 7df4d244..00000000
--- a/tests/testthat/error-complex.R
+++ /dev/null
@@ -1,5 +0,0 @@
-f <- function() g()
-g <- function() h()
-h <- function() stop("Error")
-
-f()
diff --git a/tests/testthat/error.R b/tests/testthat/error.R
deleted file mode 100644
index cf133e16..00000000
--- a/tests/testthat/error.R
+++ /dev/null
@@ -1,2 +0,0 @@
-stop("1")
-2
diff --git a/tests/testthat/example-1.R b/tests/testthat/example-1.R
deleted file mode 100644
index a2a58e0a..00000000
--- a/tests/testthat/example-1.R
+++ /dev/null
@@ -1,22 +0,0 @@
-# These test cases check that interweave
-# works for a variety of situations
-
-a <- 1  # Comment after an expression
-b <- 2
-
-{
-  a
-  b
-}
-
-# Here is a comment which should be followed
-# by two new lines
-
-{
-  print(a)  # comment in a block
-  print(b)
-}
-
-a; b
-
-a; b # Comment
diff --git a/tests/testthat/ggplot-empty-1.R b/tests/testthat/ggplot-empty-1.R
deleted file mode 100644
index 704d961e..00000000
--- a/tests/testthat/ggplot-empty-1.R
+++ /dev/null
@@ -1,4 +0,0 @@
-suppressPackageStartupMessages(library(ggplot2))
-ggplot(iris) +
-  aes(x = Speciess, y = Sepal.Length) +
-  geom_boxplot()
diff --git a/tests/testthat/ggplot-empty-2.R b/tests/testthat/ggplot-empty-2.R
deleted file mode 100644
index 15745561..00000000
--- a/tests/testthat/ggplot-empty-2.R
+++ /dev/null
@@ -1,4 +0,0 @@
-suppressPackageStartupMessages(library(ggplot2))
-ggplot(iris) +
-  aes(x = Species, y = Sepal.Length) +
-  geom_bar()
diff --git a/tests/testthat/ggplot-loop.R b/tests/testthat/ggplot-loop.R
deleted file mode 100644
index 59d8a122..00000000
--- a/tests/testthat/ggplot-loop.R
+++ /dev/null
@@ -1,6 +0,0 @@
-suppressPackageStartupMessages(library(ggplot2))
-for (j in 1:2) {
-  # ggplot2 has been loaded previously
-  print(ggplot(data.frame(x = rnorm(30), y = runif(30)), aes(x, y)) + geom_point())
-}
-
diff --git a/tests/testthat/ggplot.R b/tests/testthat/ggplot.R
deleted file mode 100644
index e631ab2f..00000000
--- a/tests/testthat/ggplot.R
+++ /dev/null
@@ -1,2 +0,0 @@
-suppressPackageStartupMessages(library(ggplot2))
-ggplot(mtcars, aes(mpg, wt)) + geom_point()
diff --git a/tests/testthat/helper.R b/tests/testthat/helper.R
new file mode 100644
index 00000000..4091f6a6
--- /dev/null
+++ b/tests/testthat/helper.R
@@ -0,0 +1,8 @@
+evaluate_ <- function(text, ...) {
+  # Trim off leading/trailing new lines and dedent
+  text <- gsub("^\n {4}", "", text)
+  text <- gsub("\n {4}", "\n", text)
+  text <- gsub("\n +$", "", text)
+  
+  evaluate(text, ...)
+}
diff --git a/tests/testthat/interleave-1.R b/tests/testthat/interleave-1.R
deleted file mode 100644
index 59042732..00000000
--- a/tests/testthat/interleave-1.R
+++ /dev/null
@@ -1,4 +0,0 @@
-for (i in 1:2) {
-  cat(i)
-  plot(i)
-}
diff --git a/tests/testthat/interleave-2.R b/tests/testthat/interleave-2.R
deleted file mode 100644
index af03d330..00000000
--- a/tests/testthat/interleave-2.R
+++ /dev/null
@@ -1,4 +0,0 @@
-for (i in 1:2) {
-  plot(i)
-  cat(i)
-}
diff --git a/tests/testthat/order.R b/tests/testthat/order.R
deleted file mode 100644
index 852dc602..00000000
--- a/tests/testthat/order.R
+++ /dev/null
@@ -1,16 +0,0 @@
-cat("1\n")
-print("2")
-warning("3")
-print("4")
-message("5")
-stop("6")
-stop("7", call. = FALSE)
-
-f <- function(x) {
-  print("8")
-  message("9")
-  warning("10")
-  stop("11")
-}
-f()
-
diff --git a/tests/testthat/parse.R b/tests/testthat/parse.R
deleted file mode 100644
index efc95a5a..00000000
--- a/tests/testthat/parse.R
+++ /dev/null
@@ -1,6 +0,0 @@
-f <- function() {
-  for (i in 1:3) {
-    plot(rnorm(100))
-    lines(rnorm(100))
-  }
-}
diff --git a/tests/testthat/plot-additions.R b/tests/testthat/plot-additions.R
deleted file mode 100644
index 253b6f9b..00000000
--- a/tests/testthat/plot-additions.R
+++ /dev/null
@@ -1,2 +0,0 @@
-plot(1:10)
-lines(1:10)
diff --git a/tests/testthat/plot-clip.R b/tests/testthat/plot-clip.R
deleted file mode 100644
index 1246cef6..00000000
--- a/tests/testthat/plot-clip.R
+++ /dev/null
@@ -1,3 +0,0 @@
-plot(rnorm(100), rnorm(100))
-clip(-1, 1, -1, 1)
-points(rnorm(100), rnorm(100), col = 'red')
diff --git a/tests/testthat/plot-last-comment.R b/tests/testthat/plot-last-comment.R
deleted file mode 100644
index 2bbd4354..00000000
--- a/tests/testthat/plot-last-comment.R
+++ /dev/null
@@ -1,4 +0,0 @@
-par(mfrow = c(3, 3))
-for (i in 1:7)
-  image(volcano)
-# comment
diff --git a/tests/testthat/plot-loop.R b/tests/testthat/plot-loop.R
deleted file mode 100644
index 10342e06..00000000
--- a/tests/testthat/plot-loop.R
+++ /dev/null
@@ -1,4 +0,0 @@
-for (i in 1:3) {
-  plot(rnorm(100))
-}
-
diff --git a/tests/testthat/plot-multi-layout.R b/tests/testthat/plot-multi-layout.R
deleted file mode 100644
index 41fb3d57..00000000
--- a/tests/testthat/plot-multi-layout.R
+++ /dev/null
@@ -1,7 +0,0 @@
-for (j in 1:3) {
-  layout(matrix(c(1, 2, 1, 3, 4, 4), 3, 2, byrow = TRUE))
-  plot(rnorm(10))
-  plot(rnorm(10))
-  plot(rnorm(10))
-  plot(rnorm(10))
-}
diff --git a/tests/testthat/plot-multi-layout2.R b/tests/testthat/plot-multi-layout2.R
deleted file mode 100644
index 20d12805..00000000
--- a/tests/testthat/plot-multi-layout2.R
+++ /dev/null
@@ -1,9 +0,0 @@
-layout(matrix(c(1, 2, 1, 3, 4, 4), 3, 2, byrow = TRUE))
-# another expression before drawing the plots
-x <- 1 + 1
-for (j in 1:2) {
-  plot(rnorm(10))
-  plot(rnorm(10))
-  plot(rnorm(10))
-  plot(rnorm(10))
-}
diff --git a/tests/testthat/plot-multi-missing.R b/tests/testthat/plot-multi-missing.R
deleted file mode 100644
index 402a9747..00000000
--- a/tests/testthat/plot-multi-missing.R
+++ /dev/null
@@ -1,4 +0,0 @@
-par(mfrow = c(2, 2))
-plot(1)
-plot(2)
-plot(3)
diff --git a/tests/testthat/plot-multi.R b/tests/testthat/plot-multi.R
deleted file mode 100644
index 6ab65579..00000000
--- a/tests/testthat/plot-multi.R
+++ /dev/null
@@ -1,5 +0,0 @@
-par(mfrow = c(2, 2))
-plot(1)
-plot(2)
-plot(3)
-plot(4)
diff --git a/tests/testthat/plot-new.R b/tests/testthat/plot-new.R
deleted file mode 100644
index 73782602..00000000
--- a/tests/testthat/plot-new.R
+++ /dev/null
@@ -1,5 +0,0 @@
-plot.new()
-plot(1:10)
-plot.new()
-plot(1:10)
-plot.new()
diff --git a/tests/testthat/plot-par.R b/tests/testthat/plot-par.R
deleted file mode 100644
index ada66433..00000000
--- a/tests/testthat/plot-par.R
+++ /dev/null
@@ -1,3 +0,0 @@
-plot(1)
-par(mar = rep(0, 4))
-plot(2)
diff --git a/tests/testthat/plot-par2.R b/tests/testthat/plot-par2.R
deleted file mode 100644
index e56c85c6..00000000
--- a/tests/testthat/plot-par2.R
+++ /dev/null
@@ -1,5 +0,0 @@
-barplot(table(mtcars$mpg), main = "All")
-# should capture all plots in this loop
-for (numcyl in levels(as.factor(mtcars$cyl))) {
-  barplot(table(mtcars$mpg[mtcars$cyl == numcyl]), main = paste("cyl = ", numcyl))
-}
diff --git a/tests/testthat/plot-persp.R b/tests/testthat/plot-persp.R
deleted file mode 100644
index 47bfa2c6..00000000
--- a/tests/testthat/plot-persp.R
+++ /dev/null
@@ -1,8 +0,0 @@
-x <- seq(-10, 10, length.out = 30)
-y <- x
-ff <- function(x,y) { r <- sqrt(x^2 + y^2); 10 * sin(r) / r }
-z <- outer(x, y, ff)
-z[is.na(z)] <- 1
-for (i in 1:3) {
-  persp(x, y, z, phi = 30 + i * 10, theta = 30)
-}
diff --git a/tests/testthat/plot-strwidth.R b/tests/testthat/plot-strwidth.R
deleted file mode 100644
index 3739b982..00000000
--- a/tests/testthat/plot-strwidth.R
+++ /dev/null
@@ -1,4 +0,0 @@
-x <- strwidth('foo', 'inches')
-y <- strheight('foo', 'inches')
-par(mar = c(4, 4, 1, 1))
-plot(1)
diff --git a/tests/testthat/plot.R b/tests/testthat/plot.R
deleted file mode 100644
index e6e140b9..00000000
--- a/tests/testthat/plot.R
+++ /dev/null
@@ -1 +0,0 @@
-plot(1:10)
diff --git a/tests/testthat/raw-output.R b/tests/testthat/raw-output.R
deleted file mode 100644
index 1f445125..00000000
--- a/tests/testthat/raw-output.R
+++ /dev/null
@@ -1,4 +0,0 @@
-rnorm(10)
-x <- list("I'm a list!")
-suppressPackageStartupMessages(library(ggplot2))
-ggplot(mtcars, aes(mpg, wt)) + geom_point()
diff --git a/tests/testthat/test-errors.R b/tests/testthat/test-errors.R
index 274f439d..163044ea 100644
--- a/tests/testthat/test-errors.R
+++ b/tests/testthat/test-errors.R
@@ -1,19 +1,25 @@
 test_that("all code run, even after error", {
-  ev <- evaluate(file("error.R"))
+  ev <- evaluate_('stop("1")\n2')
   expect_length(ev, 4)
 })
 
 test_that("code aborts on error if stop_on_error == 1L", {
-  ev <- evaluate(file("error.R"), stop_on_error = 1L)
+  ev <- evaluate('stop("1")\n2', stop_on_error = 1L)
   expect_length(ev, 2)
 })
 
 test_that("code errors if stop_on_error == 2L", {
-  expect_error(evaluate(file("error.R"), stop_on_error = 2L), "1")
+  expect_snapshot(evaluate('stop("1")', stop_on_error = 2L), error = TRUE)
 })
 
 test_that("traceback useful if stop_on_error == 2L", {
-  expect_error(evaluate(file("error-complex.R"), stop_on_error = 2L), "Error")
+  expect_error(evaluate_('
+    f <- function() g()
+    g <- function() h()
+    h <- function() stop("Error")
+
+    f()
+  ', stop_on_error = 2L), "Error")
 
   ## Doesn't work because .Traceback not create when code run
   ## inside try or tryCatch. Can't figure out how to work around.
@@ -26,6 +32,11 @@ test_that("traceback useful if stop_on_error == 2L", {
 })
 
 test_that("capture messages in try() (#88)", {
-  ev <- evaluate(file("try.R"))
+  ev <- evaluate_('
+    g <- function() f("error")
+    f <- function(x) stop(paste0("Obscure ", x))
+    
+    try(g())
+  ')  
   expect_match(ev[[length(ev)]], "Obscure error")
 })
diff --git a/tests/testthat/test-evaluate.R b/tests/testthat/test-evaluate.R
index e607d74d..8d186e19 100644
--- a/tests/testthat/test-evaluate.R
+++ b/tests/testthat/test-evaluate.R
@@ -1,5 +1,8 @@
 test_that("file with only comments runs", {
-  ev <- evaluate(file("comment.R"))
+  ev <- evaluate_("
+    # This test case contains no executable code
+    # but it shouldn't throw an error
+  ")
   expect_length(ev, 2)
 
   expect_equal(classes(ev), c("source", "source"))
@@ -8,7 +11,10 @@ test_that("file with only comments runs", {
 test_that("data sets loaded", {
   skip_if_not_installed("lattice")
 
-  ev <- evaluate(file("data.R"))
+  ev <- evaluate_('
+    data(barley, package = "lattice")
+    barley
+  ')
   expect_length(ev, 3)
 })
 
@@ -62,21 +68,38 @@ test_that("options(warn = 0) and options(warn = 1) produces warnings", {
 # })
 
 test_that("output and plots interleaved correctly", {
-  ev <- evaluate(file("interleave-1.R"))
-  expect_equal(classes(ev),
-               c("source", "character", "recordedplot", "character", "recordedplot"))
+  ev <- evaluate_("
+    for (i in 1:2) {
+      cat(i)
+      plot(i)
+    }
+  ")
+  expect_equal(
+    classes(ev),
+    c("source", "character", "recordedplot", "character", "recordedplot")
+  )
 
-  ev <- evaluate(file("interleave-2.R"))
-  expect_equal(classes(ev),
-               c("source", "recordedplot", "character", "recordedplot", "character"))
+  ev <- evaluate_("
+    for (i in 1:2) {
+      plot(i)
+      cat(i)
+    }
+  ")
+  expect_equal(
+    classes(ev),
+    c("source", "recordedplot", "character", "recordedplot", "character")
+  )
 })
 
 test_that("return value of value handler inserted directly in output list", {
   skip_if_not_installed("ggplot2")
 
-  ev <- evaluate(
-    file("raw-output.R"),
-    output_handler = new_output_handler(value = identity)
+  ev <- evaluate_('
+    rnorm(10)
+    x <- list("I\'m a list!")
+    suppressPackageStartupMessages(library(ggplot2))
+    ggplot(mtcars, aes(mpg, wt)) + geom_point()
+  ', output_handler = new_output_handler(value = identity)
   )
   expect_equal(
     classes(ev),
diff --git a/tests/testthat/test-graphics.R b/tests/testthat/test-graphics.R
index f13360fb..014f4eb0 100644
--- a/tests/testthat/test-graphics.R
+++ b/tests/testthat/test-graphics.R
@@ -1,19 +1,22 @@
 test_that("single plot is captured", {
-  ev <- evaluate(file("plot.R"))
+  ev <- evaluate("plot(1:10)")
   expect_length(ev, 2)
   expect_equal(classes(ev), c("source", "recordedplot"))
 })
 
 test_that("ggplot is captured", {
   skip_if_not_installed("ggplot2")
-
-  ev <- evaluate(file("ggplot.R"))
-  expect_length(ev, 3)
-  expect_equal(classes(ev), c("source", "source", "recordedplot"))
+  ev <- evaluate(
+    "ggplot2::ggplot(mtcars, ggplot2::aes(mpg, wt)) + ggplot2::geom_point()"
+  )
+  expect_equal(classes(ev), c("source", "recordedplot"))
 })
 
 test_that("plot additions are captured", {
-  ev <- evaluate(file("plot-additions.R"))
+  ev <- evaluate_("
+    plot(1:10)
+    lines(1:10)
+  ")
   expect_length(ev, 4)
 
   expect_equal(
@@ -23,64 +26,114 @@ test_that("plot additions are captured", {
 })
 
 test_that("blank plots by plot.new() are preserved", {
-  ev <- evaluate(file("plot-new.R"))
+  ev <- evaluate_("
+    plot.new()
+    plot(1:10)
+    plot.new()
+    plot(1:10)
+    plot.new()
+  ")
   expect_length(ev, 10)
-
-  expect_equal(
-    classes(ev),
-    rep(c("source", "recordedplot"), 5)
-  )
+  expect_equal(classes(ev), rep(c("source", "recordedplot"), 5))
 })
 
 test_that("base plots in a single expression are captured", {
-  ev <- evaluate(file("plot-loop.R"))
+  ev <- evaluate_("
+    for (i in 1:3) {
+      plot(rnorm(100))
+    }
+  ")
   expect_length(ev, 4)
-
   expect_equal(classes(ev), c("source", rep("recordedplot", 3)))
 })
 
 test_that("ggplot2 plots in a single expression are captured", {
   skip_if_not_installed("ggplot2")
 
-  ev <- evaluate(file("ggplot-loop.R"))
+  ev <- evaluate_("
+    suppressPackageStartupMessages(library(ggplot2))
+    for (j in 1:2) {
+      # ggplot2 has been loaded previously
+      print(ggplot(data.frame(x = rnorm(30), y = runif(30)), aes(x, y)) + geom_point())
+    }
+  ")
   expect_length(ev, 4)
 
   expect_equal(classes(ev), c(rep("source", 2), rep("recordedplot", 2)))
 })
 
-test_that("Empty ggplot should not be recorded", {
+test_that("erroring ggplots should not be recorded", {
   skip_if_not_installed("ggplot2")
-  ev <- evaluate(file(test_path("ggplot-empty-1.R")))
-  expect_identical(classes(ev), c(
-    "source", "source",
-    if (packageVersion("ggplot2") > "3.3.6") "rlang_error" else "simpleError"
-  ))
-  ev <- evaluate(file(test_path("ggplot-empty-2.R")))
+  
+  # error in aesthetics
+  ev <- evaluate_("
+    suppressPackageStartupMessages(library(ggplot2))
+    ggplot(iris) + aes(XXXXXXXXXX, Sepal.Length) + geom_boxplot()
+  ")
+  expect_identical(classes(ev), c("source", "source", "rlang_error"))
+  
+  # error in geom
+  ev <- evaluate_("
+    suppressPackageStartupMessages(library(ggplot2))
+    ggplot(iris) + aes(Species, Sepal.Length) + geom_bar()
+  ")
   expect_identical(classes(ev), c("source", "source", "rlang_error"))
 })
 
 test_that("multirow graphics are captured only when complete", {
-  ev <- evaluate(file("plot-multi.R"))
-
+  ev <- evaluate_("
+    par(mfrow = c(2, 2))
+    plot(1)
+    plot(2)
+    plot(3)
+    plot(4)
+  ")
   expect_equal(classes(ev), c(rep("source", 5), "recordedplot"))
 })
 
 test_that("multirow graphics are captured on close", {
-  ev <- evaluate(file("plot-multi-missing.R"))
+  ev <- evaluate_("
+    par(mfrow = c(2, 2))
+    plot(1)
+    plot(2)
+    plot(3)
+  ")
 
   expect_equal(classes(ev), c(rep("source", 4), "recordedplot"))
 })
 
 test_that("plots are captured in a non-rectangular layout", {
-  ev <- evaluate(file("plot-multi-layout.R"))
+  ev <- evaluate_("
+    for (j in 1:3) {
+      layout(matrix(c(1, 2, 1, 3, 4, 4), 3, 2, byrow = TRUE))
+      plot(rnorm(10))
+      plot(rnorm(10))
+      plot(rnorm(10))
+      plot(rnorm(10))
+    }
+  ")
   expect_equal(classes(ev), rep(c("source", "recordedplot"), c(1, 3)))
 
-  ev <- evaluate(file("plot-multi-layout2.R"))
+  ev <- evaluate_("
+    layout(matrix(c(1, 2, 1, 3, 4, 4), 3, 2, byrow = TRUE))
+    # another expression before drawing the plots
+    x <- 1 + 1
+    for (j in 1:2) {
+      plot(rnorm(10))
+      plot(rnorm(10))
+      plot(rnorm(10))
+      plot(rnorm(10))
+    }
+  ")
   expect_equal(classes(ev), rep(c("source", "recordedplot"), c(4, 2)))
 })
 
 test_that("changes in parameters don't generate new plots", {
-  ev <- evaluate(file("plot-par.R"))
+  ev <- evaluate_("
+    plot(1)
+    par(mar = rep(0, 4))
+    plot(2)
+  ")
   expect_equal(
     classes(ev),
     c("source", "recordedplot", "source", "source", "recordedplot")
@@ -88,27 +141,56 @@ test_that("changes in parameters don't generate new plots", {
 })
 
 test_that("plots in a loop are captured even the changes seem to be from par only", {
-  ev <- evaluate(file("plot-par2.R"))
+  ev <- evaluate_('
+    barplot(table(mtcars$mpg), main = "All")
+    # should capture all plots in this loop
+    for (numcyl in levels(as.factor(mtcars$cyl))) {
+      barplot(table(mtcars$mpg[mtcars$cyl == numcyl]), main = paste("cyl = ", numcyl))
+    }
+  ')
   expect_equal(classes(ev), c("source", "recordedplot")[c(1, 2, 1, 1, 2, 2, 2)])
 })
 
 test_that("strwidth()/strheight() should not produce new plots", {
-  ev <- evaluate(file("plot-strwidth.R"))
+  ev <- evaluate_("
+    x <- strwidth('foo', 'inches')
+    y <- strheight('foo', 'inches')
+    par(mar = c(4, 4, 1, 1))
+    plot(1)
+  ")
   expect_equal(classes(ev), rep(c("source", "recordedplot"), c(4, 1)))
 })
 
 test_that("clip() does not produce new plots", {
-  ev <- evaluate(file("plot-clip.R"))
+  ev <- evaluate_("
+    plot(rnorm(100), rnorm(100))
+    clip(-1, 1, -1, 1)
+    points(rnorm(100), rnorm(100), col = 'red')
+  ")
   expect_equal(classes(ev), c("source", "recordedplot")[c(1, 2, 1, 1, 2)])
 })
 
 test_that("perspective plots are captured", {
-  ev <- evaluate(file("plot-persp.R"))
+  ev <- evaluate_("
+    x <- seq(-10, 10, length.out = 30)
+    y <- x
+    ff <- function(x,y) { r <- sqrt(x^2 + y^2); 10 * sin(r) / r }
+    z <- outer(x, y, ff)
+    z[is.na(z)] <- 1
+    for (i in 1:3) {
+      persp(x, y, z, phi = 30 + i * 10, theta = 30)
+    }
+  ")
   expect_equal(classes(ev), rep(c("source", "recordedplot"), c(6, 3)))
 })
 
 test_that("an incomplete plot with a comment in the end is also captured", {
-  ev <- evaluate(file("plot-last-comment.R"))
+  ev <- evaluate_("
+    par(mfrow = c(3, 3))
+    for (i in 1:7)
+      image(volcano)
+    # comment
+  ")
   expect_equal(classes(ev), rep(c("source", "recordedplot"), c(3, 1)))
 })
 
@@ -120,7 +202,7 @@ test_that("repeatedly drawing the same plot does not omit plots randomly", {
 # test_that("no plot windows open", {
 #   graphics.off()
 #   expect_equal(length(dev.list()), 0)
-#   evaluate(file("plot.R"))
+#   evaluate("plot(1)")
 #   expect_equal(length(dev.list()), 0)
 # })
 
diff --git a/tests/testthat/test-output.R b/tests/testthat/test-output.R
index a7bc251b..ffe52daa 100644
--- a/tests/testthat/test-output.R
+++ b/tests/testthat/test-output.R
@@ -1,6 +1,6 @@
 test_that("open plot windows maintained", {
   n <- length(dev.list())
-  evaluate(file("plot.R"))
+  evaluate("plot(1)")
   expect_length(dev.list(), n)
 })
 
diff --git a/tests/testthat/try.R b/tests/testthat/try.R
deleted file mode 100644
index 5ae5daa8..00000000
--- a/tests/testthat/try.R
+++ /dev/null
@@ -1,4 +0,0 @@
-g <- function() f("error")
-f <- function(x) stop(paste0("Obscure ", x))
-
-try(g())