From 364f61221613c787ef74d76cdc02a2dee3dad5c1 Mon Sep 17 00:00:00 2001
From: noerw <noerw@gmx.de>
Date: Mon, 7 May 2018 01:09:57 +0200
Subject: [PATCH] add lintr config, make code lint compliant, fixes #20

---
 .Rbuildignore                      |   1 +
 .lintr                             |  14 ++++
 .travis.yml                        |   3 +-
 DESCRIPTION                        |   1 +
 R/00utils.R                        |   4 +-
 R/api.R                            |   2 +-
 R/box.R                            |  14 ++--
 R/box_utils.R                      |  18 ++---
 R/measurement.R                    |   2 +-
 R/measurement_utils.R              |   2 +-
 R/opensensmapr.R                   |   4 +-
 inst/doc/osem-intro.R              |   1 -
 tests/testthat.R                   |   8 +--
 tests/testthat/lint.R              |   8 +++
 tests/testthat/test_box.R          |  23 +++----
 tests/testthat/test_boxes.R        |  98 +++++++++++++--------------
 tests/testthat/test_counts.R       |  15 ++---
 tests/testthat/test_measurements.R | 105 ++++++++++++++---------------
 tests/testthat/test_phenomena.R    |  35 ++++------
 tests/testthat/testhelpers.R       |   9 +++
 20 files changed, 187 insertions(+), 180 deletions(-)
 create mode 100644 .lintr
 create mode 100644 tests/testthat/lint.R
 create mode 100644 tests/testthat/testhelpers.R

diff --git a/.Rbuildignore b/.Rbuildignore
index e42aee3..1ab258c 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -6,3 +6,4 @@
 ^appveyor\.yml$
 ^CONDUCT\.md$
 ^codecov\.yml$
+^\.lintr$
diff --git a/.lintr b/.lintr
new file mode 100644
index 0000000..ae9fe3f
--- /dev/null
+++ b/.lintr
@@ -0,0 +1,14 @@
+exclusions: list('inst/doc/osem-intro.R')
+linters: with_defaults(
+    # we use snake case
+    camel_case_linter = NULL,
+    # '=' for assignment is fine :^)
+    assignment_linter = NULL,
+    # single quotes are fine
+    single_quotes_linter = NULL,
+    # nobody reads code on a vt100 anymore
+    line_length_linter(120), 
+    # this one throws lots of false positives, dial down the noise
+    object_usage_linter = NULL,
+    NULL
+  )
diff --git a/.travis.yml b/.travis.yml
index a9e1036..851c8e2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,6 +10,7 @@ r:
 
 r_github_packages:
   - r-lib/covr
+  - jimhester/lintr
   
 before_install:
   - sudo add-apt-repository ppa:ubuntugis/ubuntugis-unstable --yes
@@ -21,4 +22,4 @@ before_install:
  
 after_success:
   - Rscript -e 'covr::codecov()'
-  #- Rscript -e 'lintr::lint_package()'
+  - Rscript -e 'lintr::lint_package()'
diff --git a/DESCRIPTION b/DESCRIPTION
index c169762..731d33b 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -18,6 +18,7 @@ Suggests:
     rmarkdown,
     lubridate,
     units,
+    lintr,
     testthat,
     covr
 Authors@R: c(person("Norwin", "Roosen", role = c("aut", "cre"), email = "bugs@nroo.de"),
diff --git a/R/00utils.R b/R/00utils.R
index fb042fb..a618dad 100644
--- a/R/00utils.R
+++ b/R/00utils.R
@@ -30,6 +30,6 @@ dplyr_class_wrapper = function(callback) {
 #'
 #' @noRd
 is_non_interactive = function () {
-  ff <- sapply(sys.calls(), function(f) as.character(f[1]))
-  any(ff %in% c("knit2html", "render")) || !interactive()
+  ff = sapply(sys.calls(), function(f) as.character(f[1]))
+  any(ff %in% c('knit2html', 'render')) || !interactive()
 }
diff --git a/R/api.R b/R/api.R
index ff7911e..aabeee2 100644
--- a/R/api.R
+++ b/R/api.R
@@ -24,7 +24,7 @@ get_boxes_ = function (..., endpoint) {
   df = dplyr::bind_rows(boxesList)
   df$exposure = df$exposure %>% as.factor()
   df$model    = df$model %>% as.factor()
-  if(!is.null(df$grouptag))
+  if (!is.null(df$grouptag))
     df$grouptag = df$grouptag %>% as.factor()
   df
 }
diff --git a/R/box.R b/R/box.R
index 49356d8..0637b39 100644
--- a/R/box.R
+++ b/R/box.R
@@ -105,23 +105,25 @@ parse_senseboxdata = function (boxdata) {
   # to allow a simple data.frame structure
   sensors = boxdata$sensors
   location = boxdata$currentLocation
-  boxdata[c('loc', 'locations', 'currentLocation', 'sensors', 'image', 'boxType')] <- NULL
+  boxdata[c('loc', 'locations', 'currentLocation', 'sensors', 'image', 'boxType')] = NULL
   thebox = as.data.frame(boxdata, stringsAsFactors = F)
 
   # parse timestamps (updatedAt might be not defined)
-  thebox$createdAt = as.POSIXct(strptime(thebox$createdAt, format='%FT%T', tz = 'GMT'))
+  thebox$createdAt = as.POSIXct(strptime(thebox$createdAt, format = '%FT%T', tz = 'GMT'))
   if (!is.null(thebox$updatedAt))
-    thebox$updatedAt = as.POSIXct(strptime(thebox$updatedAt, format='%FT%T', tz = 'GMT'))
+    thebox$updatedAt = as.POSIXct(strptime(thebox$updatedAt, format = '%FT%T', tz = 'GMT'))
 
   # extract metadata from sensors
-  thebox$phenomena = list(unlist(lapply(sensors, function(s) { s$title })))
+  thebox$phenomena = lapply(sensors, function(s) s$title) %>% unlist %>% list
+
   # FIXME: if one sensor has NA, max() returns bullshit
-  thebox$lastMeasurement = max(lapply(sensors, function(s) {
+  get_last_measurement = function(s) {
     if (!is.null(s$lastMeasurement))
       as.POSIXct(strptime(s$lastMeasurement$createdAt, format = '%FT%T', tz = 'GMT'))
     else
       NA
-  })[[1]])
+  }
+  thebox$lastMeasurement = max(lapply(sensors, get_last_measurement)[[1]])
 
   # extract coordinates & transform to simple feature object
   thebox$lon = location$coordinates[[1]]
diff --git a/R/box_utils.R b/R/box_utils.R
index 92460d1..a9f1b15 100644
--- a/R/box_utils.R
+++ b/R/box_utils.R
@@ -1,12 +1,13 @@
 #' @export
-plot.sensebox = function (x, ..., mar = c(2,2,1,1)) {
+plot.sensebox = function (x, ..., mar = c(2, 2, 1, 1)) {
   if (
-    !requireNamespace("sf", quietly = TRUE) ||
-    !requireNamespace("maps", quietly = TRUE) ||
-    !requireNamespace("maptools", quietly = TRUE) ||
-    !requireNamespace("rgeos", quietly = TRUE)
+    !requireNamespace('sf', quietly = TRUE) ||
+    !requireNamespace('maps', quietly = TRUE) ||
+    !requireNamespace('maptools', quietly = TRUE) ||
+    !requireNamespace('rgeos', quietly = TRUE)
   ) {
-    stop('this functions requires additional packages. install them with\n    install.packages(c("sf", "maps", "maptools", "rgeos"))')
+    stop('this functions requires additional packages. install them with
+    install.packages(c("sf", "maps", "maptools", "rgeos"))')
   }
 
   geom = x %>%
@@ -21,7 +22,7 @@ plot.sensebox = function (x, ..., mar = c(2,2,1,1)) {
 
   oldpar = par()
   par(mar = mar)
-  plot(world, col = 'gray', xlim = bbox[c(1,3)], ylim = bbox[c(2,4)], axes = T)
+  plot(world, col = 'gray', xlim = bbox[c(1, 3)], ylim = bbox[c(2, 4)], axes = T)
   plot(geom, add = T, col = x$exposure)
   legend('left', legend = levels(x$exposure), col = 1:length(x$exposure), pch = 1)
   par(mar = oldpar$mar)
@@ -48,7 +49,7 @@ summary.sensebox = function(object, ...) {
   table(object$model) %>% print()
   cat('\n')
 
-  diffNow = (utc_date(Sys.time()) - object$lastMeasurement) %>% as.numeric(unit='hours')
+  diffNow = (utc_date(Sys.time()) - object$lastMeasurement) %>% as.numeric(unit = 'hours')
   list(
     'last_measurement_within' = c(
       '1h'    = nrow(dplyr::filter(object, diffNow <= 1)),
@@ -122,4 +123,3 @@ mutate.sensebox = dplyr_class_wrapper(osem_as_sensebox)
 st_as_sf.sensebox = function (x, ...) {
   NextMethod(x, ..., coords = c('lon', 'lat'), crs = 4326)
 }
-
diff --git a/R/measurement.R b/R/measurement.R
index 4a56261..fb344a8 100644
--- a/R/measurement.R
+++ b/R/measurement.R
@@ -170,6 +170,6 @@ paged_measurements_req = function (query) {
     dplyr::bind_rows()
 
   # coerce all character columns (sensorId, unit, ...) to factors AFTER binding
-  df[sapply(df, is.character)] <- lapply(df[sapply(df, is.character)], as.factor)
+  df[sapply(df, is.character)] = lapply(df[sapply(df, is.character)], as.factor)
   df
 }
diff --git a/R/measurement_utils.R b/R/measurement_utils.R
index dc97c1b..de174f9 100644
--- a/R/measurement_utils.R
+++ b/R/measurement_utils.R
@@ -1,5 +1,5 @@
 #' @export
-plot.osem_measurements = function (x, ..., mar = c(2,4,1,1)) {
+plot.osem_measurements = function (x, ..., mar = c(2, 4, 1, 1)) {
   oldpar = par()
   par(mar = mar)
   plot(value~createdAt, x, col = factor(x$sensorId), xlab = NA, ylab = x$unit[1], ...)
diff --git a/R/opensensmapr.R b/R/opensensmapr.R
index e1b1833..b5eecad 100644
--- a/R/opensensmapr.R
+++ b/R/opensensmapr.R
@@ -77,6 +77,8 @@
 '_PACKAGE'
 
 #' @importFrom graphics plot legend par
-
 #' @importFrom magrittr %>%
 `%>%` = magrittr::`%>%`
+
+# just to make R CMD check happy, due to NSE (dplyr) functions
+globalVariables(c('lastMeasurement'))
diff --git a/inst/doc/osem-intro.R b/inst/doc/osem-intro.R
index 575f473..4cb7079 100644
--- a/inst/doc/osem-intro.R
+++ b/inst/doc/osem-intro.R
@@ -70,4 +70,3 @@ st_as_sf(pm25) %>% st_geometry() %>% plot(col = factor(pm25$invalid), axes = T)
 
 ## ------------------------------------------------------------------------
 pm25 %>% filter(invalid == FALSE) %>% plot()
-
diff --git a/tests/testthat.R b/tests/testthat.R
index e0e7eed..d5e0c50 100644
--- a/tests/testthat.R
+++ b/tests/testthat.R
@@ -1,5 +1,5 @@
-library("testthat")
-library("opensensmapr")
-library("sf")
+library('testthat')
+library('opensensmapr')
+library('sf')
 
-test_check("opensensmapr")
+test_check('opensensmapr')
diff --git a/tests/testthat/lint.R b/tests/testthat/lint.R
new file mode 100644
index 0000000..ecd6327
--- /dev/null
+++ b/tests/testthat/lint.R
@@ -0,0 +1,8 @@
+if (requireNamespace('lintr', quietly = TRUE)) {
+  context('lints')
+
+  test_that('Package Style', {
+    skip_on_cran()
+    lintr::expect_lint_free()
+  })
+}
diff --git a/tests/testthat/test_box.R b/tests/testthat/test_box.R
index 4d92141..db0698f 100644
--- a/tests/testthat/test_box.R
+++ b/tests/testthat/test_box.R
@@ -1,30 +1,23 @@
-context("box")
-
-check_api <- function() {
-  skip_on_cran()
-
-  code <- NA
-  try(code <- httr::status_code(httr::GET(osem_endpoint())))
-  if (is.na(code)) skip("API not available")
-}
+source('testhelpers.R')
+context('box')
 
 try({
-  boxes <- osem_boxes()
+  boxes = osem_boxes()
 })
 
-test_that("a single box can be retrieved by ID", {
+test_that('a single box can be retrieved by ID', {
   check_api()
 
-  box <- osem_box(boxes$X_id[[1]])
+  box = osem_box(boxes$X_id[[1]])
 
-  expect_true("sensebox" %in% class(box))
-  expect_true("data.frame" %in% class(box))
+  expect_true('sensebox' %in% class(box))
+  expect_true('data.frame' %in% class(box))
   expect_true(nrow(box) == 1)
   expect_true(box$X_id == boxes$X_id[[1]])
 })
 
 
-test_that("[.sensebox maintains attributes", {
+test_that('[.sensebox maintains attributes', {
   check_api()
 
   expect_true(all(attributes(boxes[1:nrow(boxes), ]) %in% attributes(boxes)))
diff --git a/tests/testthat/test_boxes.R b/tests/testthat/test_boxes.R
index c0d925e..96e0262 100644
--- a/tests/testthat/test_boxes.R
+++ b/tests/testthat/test_boxes.R
@@ -1,112 +1,108 @@
-context("boxes")
+source('testhelpers.R')
+context('boxes')
 
-check_api <- function() {
-  skip_on_cran()
-
-  code <- NA
-  try(code <- httr::status_code(httr::GET(osem_endpoint())))
-  if (is.na(code)) skip("API not available")
-}
-
-test_that("a list of all boxes can be retrieved and returns a sensebox data.frame", {
+test_that('a list of all boxes can be retrieved and returns a sensebox data.frame', {
   check_api()
 
-  boxes <- osem_boxes()
+  boxes = osem_boxes()
   expect_true(is.data.frame(boxes))
   expect_true(is.factor(boxes$model))
   expect_true(is.character(boxes$name))
   expect_length(names(boxes), 14)
-  expect_true(any("sensebox" %in% class(boxes)))
+  expect_true(any('sensebox' %in% class(boxes)))
 })
 
-test_that("both from and to are required when requesting boxes, error otherwise", {
-  expect_error(osem_boxes(from = as.POSIXct("2017-01-01")), "must be used together")
-  expect_error(osem_boxes(to   = as.POSIXct("2017-01-01")), "must be used together")
+test_that('both from and to are required when requesting boxes, error otherwise', {
+  expect_error(osem_boxes(from = as.POSIXct('2017-01-01')), 'must be used together')
+  expect_error(osem_boxes(to   = as.POSIXct('2017-01-01')), 'must be used together')
 })
 
-test_that("a list of boxes with exposure filter returns only the requested exposure", {
+test_that('a list of boxes with exposure filter returns only the requested exposure', {
   check_api()
 
-  boxes <- osem_boxes(exposure = "mobile")
-  expect_true(all(boxes$exposure == "mobile"))
+  boxes = osem_boxes(exposure = 'mobile')
+  expect_true(all(boxes$exposure == 'mobile'))
 })
 
-test_that("a list of boxes with model filter returns only the requested model", {
+test_that('a list of boxes with model filter returns only the requested model', {
   check_api()
 
-  boxes <- osem_boxes(model = "homeWifi")
-  expect_true(all(boxes$model == "homeWifi"))
+  boxes = osem_boxes(model = 'homeWifi')
+  expect_true(all(boxes$model == 'homeWifi'))
 })
 
-test_that("box query can combine exposure and model filter", {
+test_that('box query can combine exposure and model filter', {
   check_api()
 
-  boxes <- osem_boxes(exposure = "mobile", model = "homeWifi")
-  expect_true(all(boxes$model == "homeWifi"))
-  expect_true(all(boxes$exposure == "mobile"))
+  boxes = osem_boxes(exposure = 'mobile', model = 'homeWifi')
+  expect_true(all(boxes$model == 'homeWifi'))
+  expect_true(all(boxes$exposure == 'mobile'))
 })
 
-test_that("a list of boxes with grouptype returns only boxes of that group", {
+test_that('a list of boxes with grouptype returns only boxes of that group', {
   check_api()
 
-  boxes <- osem_boxes(grouptag = "codeformuenster")
-  expect_true(all(boxes$grouptag == "codeformuenster"))
+  boxes = osem_boxes(grouptag = 'codeformuenster')
+  expect_true(all(boxes$grouptag == 'codeformuenster'))
 })
 
-test_that("endpoint can be (mis)configured", {
+test_that('endpoint can be (mis)configured', {
   check_api()
 
-  expect_error(osem_boxes(endpoint = "http://not.the.opensensemap.org"), "resolve host")
+  expect_error(osem_boxes(endpoint = 'http://not.the.opensensemap.org'), 'resolve host')
 })
 
-test_that("a response with no matches returns empty sensebox data.frame and a warning", {
+test_that('a response with no matches returns empty sensebox data.frame', {
   check_api()
 
-  suppressWarnings(boxes <- osem_boxes(grouptag = "does_not_exist"))
+  suppressWarnings({
+    boxes = osem_boxes(grouptag = 'does_not_exist')
+  })
   expect_true(is.data.frame(boxes))
-  expect_true(any("sensebox" %in% class(boxes)))
+  expect_true(any('sensebox' %in% class(boxes)))
 })
 
-test_that("a response with no matches gives a warning", {
+test_that('a response with no matches gives a warning', {
   check_api()
 
-  expect_warning(osem_boxes(grouptag = "does_not_exist"), "no senseBoxes found")
+  expect_warning(osem_boxes(grouptag = 'does_not_exist'), 'no senseBoxes found')
 })
 
-test_that("data.frame can be converted to sensebox data.frame", {
-  df <- osem_as_sensebox(data.frame(c(1,2), c("a", "b")))
-  expect_equal(class(df), c("sensebox", "data.frame"))
+test_that('data.frame can be converted to sensebox data.frame', {
+  df = osem_as_sensebox(data.frame(c(1, 2), c('a', 'b')))
+  expect_equal(class(df), c('sensebox', 'data.frame'))
 })
 
-test_that("boxes can be converted to sf object", {
+test_that('boxes can be converted to sf object', {
   check_api()
 
-  boxes <- osem_boxes()
-  boxes_sf <- sf::st_as_sf(boxes)
+  boxes = osem_boxes()
+  boxes_sf = sf::st_as_sf(boxes)
 
   expect_true(all(sf::st_is_simple(boxes_sf)))
-  expect_true("sf" %in% class(boxes_sf))
+  expect_true('sf' %in% class(boxes_sf))
 })
 
-test_that("boxes converted to sf object keep all attributes", {
+test_that('boxes converted to sf object keep all attributes', {
   check_api()
 
-  boxes <- osem_boxes()
-  boxes_sf <- sf::st_as_sf(boxes)
+  boxes = osem_boxes()
+  boxes_sf = sf::st_as_sf(boxes)
 
   # coord columns get removed!
-  cols <- names(boxes)[!names(boxes) %in% c('lon', 'lat')]
+  cols = names(boxes)[!names(boxes) %in% c('lon', 'lat')]
   expect_true(all(cols %in% names(boxes_sf)))
 
-  expect_true("sensebox" %in% class(boxes_sf))
+  expect_true('sensebox' %in% class(boxes_sf))
 })
 
-test_that("box retrieval does not give progress information in non-interactive mode", {
+test_that('box retrieval does not give progress information in non-interactive mode', {
   check_api()
 
-  if (!opensensmapr:::is_non_interactive()) skip("interactive session")
+  if (!opensensmapr:::is_non_interactive()) skip('interactive session')
 
-  out <- capture.output(b <- osem_boxes())
+  out = capture.output({
+    b = osem_boxes()
+  })
   expect_length(out, 0)
 })
-
diff --git a/tests/testthat/test_counts.R b/tests/testthat/test_counts.R
index f4c7d6a..5678ac2 100644
--- a/tests/testthat/test_counts.R
+++ b/tests/testthat/test_counts.R
@@ -1,17 +1,10 @@
-context("counts")
+source('testhelpers.R')
+context('counts')
 
-check_api <- function() {
-  skip_on_cran()
-
-  code <- NA
-  try(code <- httr::status_code(httr::GET(osem_endpoint())))
-  if (is.na(code)) skip("API not available")
-}
-
-test_that("counts can be retrieved as a list of numbers", {
+test_that('counts can be retrieved as a list of numbers', {
   check_api()
 
-  counts <- osem_counts()
+  counts = osem_counts()
 
   expect_true(is.list(counts))
   expect_true(is.numeric(unlist(counts)))
diff --git a/tests/testthat/test_measurements.R b/tests/testthat/test_measurements.R
index fb85bd7..9d181cc 100644
--- a/tests/testthat/test_measurements.R
+++ b/tests/testthat/test_measurements.R
@@ -1,121 +1,116 @@
-context("measurements")
-
-check_api <- function() {
-  skip_on_cran()
-
-  code <- NA
-  try(code <- httr::status_code(httr::GET(osem_endpoint())))
-  if (is.na(code)) skip("API not available")
-}
+source('testhelpers.R')
+context('measurements')
 
 try({
-  boxes <- osem_boxes()
- })
+  boxes = osem_boxes()
+})
 
-test_that("measurements can be retrieved for a phenomenon", {
+test_that('measurements can be retrieved for a phenomenon', {
   check_api()
 
-  measurements <- osem_measurements(x = "Windgeschwindigkeit")
+  measurements = osem_measurements(x = 'Windgeschwindigkeit')
   expect_true(is.data.frame(measurements))
-  expect_true("osem_measurements" %in% class(measurements))
+  expect_true('osem_measurements' %in% class(measurements))
 })
 
-test_that("measurement retrieval does not give progress information in non-interactive mode", {
+test_that('measurement retrieval does not give progress information in non-interactive mode', {
   check_api()
 
-  if (!opensensmapr:::is_non_interactive()) skip("interactive session")
+  if (!opensensmapr:::is_non_interactive()) skip('interactive session')
 
-  out <- capture.output(measurements <- osem_measurements(x = "Licht"))
+  out = capture.output({
+    measurements = osem_measurements(x = 'Licht')
+  })
   expect_length(out, 0)
 })
 
-test_that("a response with no matching senseBoxes gives an error", {
+test_that('a response with no matching senseBoxes gives an error', {
   check_api()
 
-  expect_error(osem_measurements(x = "Windgeschwindigkeit", exposure = "indoor"), "No senseBoxes found")
+  expect_error(osem_measurements(x = 'Windgeschwindigkeit', exposure = 'indoor'), 'No senseBoxes found')
 })
 
-test_that("data.frame can be converted to measurements data.frame", {
-  df <- osem_as_measurements(data.frame(c(1,2), c("a", "b")))
-  expect_equal(class(df), c("osem_measurements", "data.frame"))
+test_that('data.frame can be converted to measurements data.frame', {
+  df = osem_as_measurements(data.frame(c(1, 2), c('a', 'b')))
+  expect_equal(class(df), c('osem_measurements', 'data.frame'))
 })
 
-test_that("columns can be specified for phenomena", {
+test_that('columns can be specified for phenomena', {
   check_api()
 
-  cols <- c("value", "boxId", "boxName")
-  measurements <- osem_measurements(x = "Windgeschwindigkeit", columns = cols)
+  cols = c('value', 'boxId', 'boxName')
+  measurements = osem_measurements(x = 'Windgeschwindigkeit', columns = cols)
   expect_equal(names(measurements), cols)
 })
 
-test_that("measurements can be retrieved for a phenomenon and exposure", {
+test_that('measurements can be retrieved for a phenomenon and exposure', {
   check_api()
 
-  measurements <- osem_measurements(x = "Temperatur", exposure = "unknown",
-                                    columns = c("value", "boxId", "boxName"))
+  measurements = osem_measurements(x = 'Temperatur', exposure = 'unknown',
+                                    columns = c('value', 'boxId', 'boxName'))
   expect_equal(nrow(measurements), 0)
 })
 
-test_that("measurements of specific boxes can be retrieved for one phenomenon and returns a measurements data.frame", {
+test_that('measurements of specific boxes can be retrieved for one phenomenon and returns a measurements data.frame', {
   check_api()
 
   # fix for subsetting
-  class(boxes) <- c("data.frame")
-  three_boxes <- boxes[1:3,]
-  class(boxes) <- c("sensebox", "data.frame")
-  three_boxes <- osem_as_sensebox(three_boxes)
-  phens <- names(osem_phenomena(three_boxes))
+  class(boxes) = c('data.frame')
+  three_boxes = boxes[1:3, ]
+  class(boxes) = c('sensebox', 'data.frame')
+  three_boxes = osem_as_sensebox(three_boxes)
+  phens = names(osem_phenomena(three_boxes))
 
-  measurements <- osem_measurements(x = three_boxes, phenomenon = phens[[1]])
+  measurements = osem_measurements(x = three_boxes, phenomenon = phens[[1]])
   expect_true(is.data.frame(measurements))
-  expect_true("osem_measurements" %in% class(measurements))
+  expect_true('osem_measurements' %in% class(measurements))
 })
 
-test_that("measurements can be retrieved for a bounding box", {
+test_that('measurements can be retrieved for a bounding box', {
   check_api()
 
-  sfc <- sf::st_sfc(sf::st_linestring(x = matrix(data = c(7, 8, 50, 51), ncol = 2)), crs = 4326)
-  bbox <- sf::st_bbox(sfc)
-  measurements <- osem_measurements(x = bbox, phenomenon = "Windrichtung")
+  sfc = sf::st_sfc(sf::st_linestring(x = matrix(data = c(7, 8, 50, 51), ncol = 2)), crs = 4326)
+  bbox = sf::st_bbox(sfc)
+  measurements = osem_measurements(x = bbox, phenomenon = 'Windrichtung')
   expect_true(all(unique(measurements$lat) > 50))
   expect_true(all(unique(measurements$lat) < 51))
   expect_true(all(unique(measurements$lon) < 8))
   expect_true(all(unique(measurements$lon) > 7))
 })
 
-test_that("measurements can be retrieved for a time period", {
+test_that('measurements can be retrieved for a time period', {
   check_api()
 
-  from_date <- as.POSIXct("2018-01-01 12:00:00")
-  to_date <- as.POSIXct("2018-01-01 13:00:00")
-  measurements <- osem_measurements(x = "Temperature", from = from_date, to = to_date)
+  from_date = as.POSIXct('2018-01-01 12:00:00')
+  to_date = as.POSIXct('2018-01-01 13:00:00')
+  measurements = osem_measurements(x = 'Temperature', from = from_date, to = to_date)
 
   expect_true(all(measurements$createdAt < to_date))
   expect_true(all(measurements$createdAt > from_date))
 })
 
-test_that("measurements can be retrieved for a time period > 31 days", {
+test_that('measurements can be retrieved for a time period > 31 days', {
   check_api()
 
-  from_date <- as.POSIXct("2017-11-01 12:00:00")
-  to_date <- as.POSIXct("2018-01-01 13:00:00")
-  measurements <- osem_measurements(x = "Windrichtung", from = from_date, to = to_date)
+  from_date = as.POSIXct('2017-11-01 12:00:00')
+  to_date = as.POSIXct('2018-01-01 13:00:00')
+  measurements = osem_measurements(x = 'Windrichtung', from = from_date, to = to_date)
 
   expect_true(all(measurements$createdAt < to_date))
   expect_true(all(measurements$createdAt > from_date))
 })
 
-test_that("both from and to are required when requesting measurements, error otherwise", {
-  expect_error(osem_measurements(x = "Temperature", from = as.POSIXct("2017-01-01")), "only together with")
-  expect_error(osem_measurements(x = "Temperature", to   = as.POSIXct("2017-01-01")), "only together with")
+test_that('both from and to are required when requesting measurements, error otherwise', {
+  expect_error(osem_measurements(x = 'Temperature', from = as.POSIXct('2017-01-01')), 'only together with')
+  expect_error(osem_measurements(x = 'Temperature', to   = as.POSIXct('2017-01-01')), 'only together with')
 })
 
-test_that("[.osem_measurements maintains attributes", {
+test_that('[.osem_measurements maintains attributes', {
   check_api()
 
-  sfc <- sf::st_sfc(sf::st_linestring(x = matrix(data = c(7, 8, 50, 51), ncol = 2)), crs = 4326)
-  bbox <- sf::st_bbox(sfc)
-  m <- osem_measurements(x = bbox, phenomenon = "Windrichtung")
+  sfc = sf::st_sfc(sf::st_linestring(x = matrix(data = c(7, 8, 50, 51), ncol = 2)), crs = 4326)
+  bbox = sf::st_bbox(sfc)
+  m = osem_measurements(x = bbox, phenomenon = 'Windrichtung')
 
   expect_true(all(attributes(m[1:nrow(m), ]) %in% attributes(m)))
 })
diff --git a/tests/testthat/test_phenomena.R b/tests/testthat/test_phenomena.R
index 5cf7682..557b982 100644
--- a/tests/testthat/test_phenomena.R
+++ b/tests/testthat/test_phenomena.R
@@ -1,40 +1,33 @@
-context("phenomena")
-
-check_api <- function() {
-  skip_on_cran()
-
-  code <- NA
-  try(code <- httr::status_code(httr::GET(osem_endpoint())))
-  if (is.na(code)) skip("API not available")
-}
+source('testhelpers.R')
+context('phenomena')
 
 try({
-  boxes <- osem_boxes()
-  all_phen <- unique(unlist(boxes$phenomena))
+  boxes = osem_boxes()
+  all_phen = unique(unlist(boxes$phenomena))
 })
 
-test_that("phenomena from boxes is a list of counts", {
+test_that('phenomena from boxes is a list of counts', {
   check_api()
 
-  phenomena <- osem_phenomena(boxes)
+  phenomena = osem_phenomena(boxes)
 
   expect_true(is.numeric(unlist(phenomena)))
   expect_true(is.list(phenomena))
 })
 
-test_that("phenomena from boxes has all phenomena", {
+test_that('phenomena from boxes has all phenomena', {
   check_api()
 
-  phenomena <- osem_phenomena(boxes)
+  phenomena = osem_phenomena(boxes)
 
   expect_true(all(all_phen %in% names(phenomena)))
   expect_true(all(names(phenomena) %in% all_phen))
 })
 
-test_that("phenomena from a not sensebox data.frame returns error", {
-  expect_error(osem_phenomena(list()), "no applicable method")
-  expect_error(osem_phenomena(data.frame()), "no applicable method")
-  boxes_df <- boxes
-  class(boxes_df) <- c("data.frame")
-  expect_error(osem_phenomena(boxes_df), "no applicable method")
+test_that('phenomena from a not sensebox data.frame returns error', {
+  expect_error(osem_phenomena(list()), 'no applicable method')
+  expect_error(osem_phenomena(data.frame()), 'no applicable method')
+  boxes_df = boxes
+  class(boxes_df) = c('data.frame')
+  expect_error(osem_phenomena(boxes_df), 'no applicable method')
 })
diff --git a/tests/testthat/testhelpers.R b/tests/testthat/testhelpers.R
new file mode 100644
index 0000000..ac9e420
--- /dev/null
+++ b/tests/testthat/testhelpers.R
@@ -0,0 +1,9 @@
+check_api = function() {
+  skip_on_cran()
+
+  code = NA
+  try({
+    code = httr::status_code(httr::GET(osem_endpoint()))
+  })
+  if (is.na(code)) skip('API not available')
+}