[SPARK-23435][SPARKR][TESTS] Update testthat to >= 2.0.0

### What changes were proposed in this pull request?

- Update `testthat` to >= 2.0.0
- Replace of `testthat:::run_tests` with `testthat:::test_package_dir`
- Add trivial assertions for tests, without any expectations, to avoid skipping.
- Update related docs.

### Why are the changes needed?

`testthat` version has been frozen by [SPARK-22817](https://issues.apache.org/jira/browse/SPARK-22817) / https://github.com/apache/spark/pull/20003, but 1.0.2 is pretty old, and we shouldn't keep things in this state forever.

### Does this PR introduce any user-facing change?

No.

### How was this patch tested?

- Existing CI pipeline:
     - Windows build on AppVeyor, R 3.6.2, testthtat 2.3.1
     - Linux build on Jenkins, R 3.1.x, testthat 1.0.2

- Additional builds with thesthat 2.3.1  using [sparkr-build-sandbox](https://github.com/zero323/sparkr-build-sandbox) on c7ed64af9e697b3619779857dd820832176b3be3

   R 3.4.4  (image digest ec9032f8cf98)
   ```
   docker pull zero323/sparkr-build-sandbox:3.4.4
   docker run zero323/sparkr-build-sandbox:3.4.4 zero323 --branch SPARK-23435 --commit c7ed64af9e697b3619779857dd820832176b3be3 --public-key https://keybase.io/zero323/pgp_keys.asc
    ```
    3.5.3 (image digest 0b1759ee4d1d)

    ```
    docker pull zero323/sparkr-build-sandbox:3.5.3
    docker run zero323/sparkr-build-sandbox:3.5.3 zero323 --branch SPARK-23435 --commit
    c7ed64af9e697b3619779857dd820832176b3be3 --public-key https://keybase.io/zero323/pgp_keys.asc
    ```

   and 3.6.2 (image digest 6594c8ceb72f)
    ```
   docker pull zero323/sparkr-build-sandbox:3.6.2
   docker run zero323/sparkr-build-sandbox:3.6.2 zero323 --branch SPARK-23435 --commit c7ed64af9e697b3619779857dd820832176b3be3 --public-key https://keybase.io/zero323/pgp_keys.asc
   ````

   Corresponding [asciicast](https://asciinema.org/) are available as 10.5281/zenodo.3629431

     [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.3629431.svg)](https://doi.org/10.5281/zenodo.3629431)

   (a bit to large to burden asciinema.org, but can run locally via `asciinema play`).

----------------------------

Continued from #27328

Closes #27359 from zero323/SPARK-23435.

Authored-by: zero323 <mszymkiewicz@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>

R/pkg/tests/fulltests/test_context.R

@@ -84,6 +84,7 @@ test_that("rdd GC across sparkR.stop", {
   countRDD(rdd3)
   countRDD(rdd4)
   sparkR.session.stop()
+  expect_true(TRUE)
 })
 
 test_that("job group functions can be called", {
@@ -93,6 +94,7 @@ test_that("job group functions can be called", {
   clearJobGroup()
 
   sparkR.session.stop()
+  expect_true(TRUE)
 })
 
 test_that("job description and local properties can be set and got", {
@@ -131,6 +133,7 @@ test_that("utility function can be called", {
   sparkR.sparkContext(master = sparkRTestMaster)
   setLogLevel("ERROR")
   sparkR.session.stop()
+  expect_true(TRUE)
 })
 
 test_that("getClientModeSparkSubmitOpts() returns spark-submit args from whitelist", {
@@ -234,4 +237,5 @@ test_that("SPARK-25234: parallelize should not have integer overflow", {
   # 47000 * 47000 exceeds integer range
   parallelize(sc, 1:47000, 47000)
   sparkR.session.stop()
+  expect_true(TRUE)
 })

R/pkg/tests/fulltests/test_includePackage.R

@@ -39,6 +39,7 @@ test_that("include inside function", {
     data <- lapplyPartition(rdd, generateData)
     actual <- collectRDD(data)
   }
+  expect_true(TRUE)
 })
 
 test_that("use include package", {
@@ -55,6 +56,7 @@ test_that("use include package", {
     data <- lapplyPartition(rdd, generateData)
     actual <- collectRDD(data)
   }
+  expect_true(TRUE)
 })
 
 sparkR.session.stop()

R/pkg/tests/fulltests/test_sparkSQL.R

@@ -1382,6 +1382,7 @@ test_that("column operators", {
   c5 <- c2 ^ c3 ^ c4
   c6 <- c2 %<=>% c3
   c7 <- !c6
+  expect_true(TRUE)
 })
 
 test_that("column functions", {

R/pkg/tests/fulltests/test_textFile.R

@@ -75,6 +75,7 @@ test_that("several transformations on RDD created by textFile()", {
   collectRDD(rdd)
 
   unlink(fileName)
+  expect_true(TRUE)
 })
 
 test_that("textFile() followed by a saveAsTextFile() returns the same content", {

R/pkg/tests/run-all.R

@@ -20,7 +20,6 @@ library(SparkR)
 
 # SPARK-25572
 if (identical(Sys.getenv("NOT_CRAN"), "true")) {
-
   # Turn all warnings into errors
   options("warn" = 2)
 
@@ -60,11 +59,23 @@ if (identical(Sys.getenv("NOT_CRAN"), "true")) {
   if (identical(Sys.getenv("NOT_CRAN"), "true")) {
     # set random seed for predictable results. mostly for base's sample() in tree and classification
     set.seed(42)
-    # for testthat 1.0.2 later, change reporter from "summary" to default_reporter()
-    testthat:::run_tests("SparkR",
+
+    # TODO (SPARK-30663) To be removed once testthat 1.x is removed from all builds
+    if (grepl("^1\\..*", packageVersion("testthat"))) {
+      # testthat 1.x
+      test_runner <- testthat:::run_tests
+      reporter <- "summary"
+
+    } else {
+      # testthat >= 2.0.0
+      test_runner <- testthat:::test_package_dir
+      reporter <- testthat::default_reporter()
+    }
+
+    test_runner("SparkR",
                 file.path(sparkRDir, "pkg", "tests", "fulltests"),
                 NULL,
-                         "summary")
+                reporter)
   }
 
   SparkR:::uninstallDownloadedSpark()

appveyor.yml

@@ -43,11 +43,7 @@ install:
   - ps: .\dev\appveyor-install-dependencies.ps1
   # Required package for R unit tests
   - cmd: R -e "install.packages(c('knitr', 'rmarkdown', 'e1071', 'survival', 'arrow'), repos='https://cloud.r-project.org/')"
-  # Here, we use the fixed version of testthat. For more details, please see SPARK-22817.
-  # As of devtools 2.1.0, it requires testthat higher then 2.1.1 as a dependency. SparkR test requires testthat 1.0.2.
-  # Therefore, we don't use devtools but installs it directly from the archive including its dependencies.
-  - cmd: R -e "install.packages(c('crayon', 'praise', 'R6'), repos='https://cloud.r-project.org/')"
-  - cmd: R -e "install.packages('https://cloud.r-project.org/src/contrib/Archive/testthat/testthat_1.0.2.tar.gz', repos=NULL, type='source')"
+  - cmd: R -e "install.packages(c('crayon', 'praise', 'R6', 'testthat'), repos='https://cloud.r-project.org/')"
   - cmd: R -e "packageVersion('knitr'); packageVersion('rmarkdown'); packageVersion('testthat'); packageVersion('e1071'); packageVersion('survival'); packageVersion('arrow')"
 
 build_script:

docs/README.md

@@ -39,9 +39,8 @@ installed. Also install the following libraries:
 $ sudo gem install jekyll jekyll-redirect-from rouge
 # Following is needed only for generating API docs
 $ sudo pip install sphinx pypandoc mkdocs
-$ sudo Rscript -e 'install.packages(c("knitr", "devtools", "rmarkdown"), repos="https://cloud.r-project.org/")'
+$ sudo Rscript -e 'install.packages(c("knitr", "devtools", "testthat", "rmarkdown"), repos="https://cloud.r-project.org/")'
 $ sudo Rscript -e 'devtools::install_version("roxygen2", version = "5.0.1", repos="https://cloud.r-project.org/")'
-$ sudo Rscript -e 'devtools::install_version("testthat", version = "1.0.2", repos="https://cloud.r-project.org/")'
 ```
 
 Note: If you are on a system with both Ruby 1.9 and Ruby 2.0 you may need to replace gem with gem2.0.

docs/building-spark.md

@@ -238,8 +238,7 @@ The run-tests script also can be limited to a specific Python version or a speci
 
 To run the SparkR tests you will need to install the [knitr](https://cran.r-project.org/package=knitr), [rmarkdown](https://cran.r-project.org/package=rmarkdown), [testthat](https://cran.r-project.org/package=testthat), [e1071](https://cran.r-project.org/package=e1071) and [survival](https://cran.r-project.org/package=survival) packages first:
 
-    Rscript -e "install.packages(c('knitr', 'rmarkdown', 'devtools', 'e1071', 'survival'), repos='https://cloud.r-project.org/')"
-    Rscript -e "devtools::install_version('testthat', version = '1.0.2', repos='https://cloud.r-project.org/')"
+    Rscript -e "install.packages(c('knitr', 'rmarkdown', 'devtools', 'testthat', 'e1071', 'survival'), repos='https://cloud.r-project.org/')"
 
 You can run just the SparkR tests using the command: