Add unit tests for run_now()

Author: jcheng5

.Rbuildignore

@@ -1,3 +1,4 @@
 ^.*\.Rproj$
 ^\.Rproj\.user$
-.travis.yml
+.travis.yml
+^include$

DESCRIPTION

@@ -18,6 +18,8 @@ Imports:
 LinkingTo: Rcpp, BH
 Roxygen: list(markdown = TRUE)
 RoxygenNote: 6.0.1
-Suggests: knitr,
-    rmarkdown
+Suggests:
+    knitr,
+    rmarkdown,
+    testthat
 VignetteBuilder: knitr

include

@@ -0,0 +1 @@
+inst/include

inst/bgtest.cpp

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+#include <later_api.h>
+#include <unistd.h>
+
+// Used in tests/testthat/test-run_now.R
+
+class TestTask : public later::BackgroundTask {
+  int _timeoutSecs;
+
+public:
+  TestTask(int timeoutSecs) : _timeoutSecs(timeoutSecs) {}
+
+protected:
+  // The task to be executed on the background thread.
+  // Neither the R runtime nor any R data structures may be
+  // touched from the background thread; any values that need
+  // to be passed into or out of the Execute method must be
+  // included as fields on the Task subclass object.
+  void execute() {
+    sleep(_timeoutSecs);
+  }
+
+  // A short task that runs on the main R thread after the
+  // background task has completed. It's safe to access the
+  // R runtime and R data structures from here.
+  void complete() {}
+};
+
+
+// [[Rcpp::depends(later)]]
+// [[Rcpp::export]]
+void launchBgTask(int secsToSleep) {
+  (new TestTask(secsToSleep))->begin();
+}

tests/testthat.R

@@ -0,0 +1,7 @@
+# See https://github.com/r-lib/testthat/issues/86
+Sys.setenv("R_TESTS" = "")
+
+library(testthat)
+library(later)
+
+test_check("later")

tests/testthat/test-run_now.R

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+context("test-run_now.R")
+
+test_that("run_now waits and returns FALSE if no tasks", {
+  x <- system.time({
+    result <- later::run_now(0.5)
+  })
+  expect_gte(as.numeric(x[["elapsed"]]), 0.499)
+  expect_identical(result, FALSE)
+
+  x <- system.time({
+    result <- later::run_now(3)
+  })
+  expect_gte(as.numeric(x[["elapsed"]]), 2.999)
+  expect_identical(result, FALSE)
+})
+
+test_that("run_now returns immediately after executing a task", {
+  x <- system.time({
+    later::later(~{}, 0)
+    result <- later::run_now(2)
+  })
+  expect_lt(as.numeric(x[["elapsed"]]), 0.25)
+  expect_identical(result, TRUE)
+})
+
+test_that("run_now executes all scheduled tasks, not just one", {
+  later::later(~{}, 0)
+  later::later(~{}, 0)
+  result1 <- later::run_now()
+  result2 <- later::run_now()
+  expect_identical(result1, TRUE)
+  expect_identical(result2, FALSE)
+})
+
+test_that("run_now doesn't go past a failed task", {
+  later::later(~stop("boom"), 0)
+  later::later(~{}, 0)
+  expect_error(later::run_now())
+  expect_true(later::run_now())
+})
+
+test_that("run_now wakes up when a background thread calls later()", {
+  env <- new.env()
+  Rcpp::sourceCpp(system.file("bgtest.cpp", package = "later"), env = env)
+  # The background task sleeps
+  env$launchBgTask(1)
+
+  x <- system.time({
+    result <- later::run_now(3)
+  })
+  expect_lt(as.numeric(x[["elapsed"]]), 1.25)
+  expect_true(result)
+})