diff --git a/R/mergePHBfilePairs.R b/R/mergePHBfilePairs.R
index 6281b8f..2333217 100644
--- a/R/mergePHBfilePairs.R
+++ b/R/mergePHBfilePairs.R
@@ -1,57 +1,40 @@
-mergePHBfilePairs = function(inputPath = ".", outputPath = ".",
+mergePHBfilePairs = function(filenames = NULL,
                              timeformat = "%m/%d/%Y %H:%M:%S",
                              desiredtz = "", configtz = NULL,
                              timeformatName = "timeformat") {
   # merges Philips Health Band xlsx files per participant
   # as there can be multiple files per participant.
-  fnames = dir(inputPath, recursive = FALSE, full.names = TRUE, pattern = "[.]xlsx")
-  fileOverview = data.frame(filename = fnames)
-  extractID = function(x) {
-    x = basename(x)
-    x = gsub(pattern = "sleep_wake", replacement = "sleepwake", x = tolower(x))
-    ID = unlist(strsplit(x, "_"))[2]
-    return(ID)
+  if (length(filenames) != 2) {
+    stop("Provide two filenames")
   }
-  fileOverview$ID = unlist(lapply(fileOverview$filename, FUN = extractID))
   
-  uids = unique(fileOverview$ID)
-  for (uid in uids) {
-    filesForThisPerson = fileOverview$filename[which(fileOverview$ID == uid)]
-    # Identify both file
-    file1 = grep(pattern = "datalist", x = filesForThisPerson, ignore.case = TRUE)
-    file2 = grep(pattern = "sleep_wake", x = filesForThisPerson, ignore.case = TRUE)
-    if (length(file1) == 0 && length(file2) == 0) {
-      next
-    }
-    # Data
-    deviceSN = NULL
+  # Identify both file
+  file1 = grep(pattern = "datalist", x = filenames, ignore.case = TRUE)
+  file2 = grep(pattern = "sleep_wake", x = filenames, ignore.case = TRUE)
+
+  # Datalist file (with all variables except sleep/wake scores)
+  deviceSN = NULL
+  if (length(file1) > 0) {
+    data1 = readPHBCount(filename = filenames[file1], timeformat = timeformat,
+                         desiredtz = desiredtz, configtz = configtz,
+                         timeformatName = timeformatName)
+    deviceSN = data1$deviceSN
+  }
+  # Sleep wake scores file
+  if (length(file2) > 0) {
+    data2 = readPHBCount(filename = filenames[file2], timeformat = timeformat,
+                         desiredtz = desiredtz, configtz = configtz,
+                         timeformatName = timeformatName)
+  }
+  if (length(file1) > 0 && length(file2) > 0) {
+    data2$data = data2$data[, which(colnames(data2$data) != "sleepEventMarker")]
+    data = merge(data1$data, data2$data, by = "timestamp")
+  } else {
     if (length(file1) > 0) {
-      data1 = readPHBCount(filename = filesForThisPerson[file1], timeformat = timeformat,
-                   desiredtz = desiredtz, configtz = configtz,
-                   timeformatName = timeformatName)
-      deviceSN = data1$deviceSN
-    }
-    # Sleep wake scores
-    if (length(file2) > 0) {
-      data2 = readPHBCount(filename = filesForThisPerson[file2], timeformat = timeformat,
-                           desiredtz = desiredtz, configtz = configtz,
-                           timeformatName = timeformatName)
-    }
-    if (length(file1) > 0 && length(file2) > 0) {
-      data2$data = data2$data[, which(colnames(data2$data) != "sleepEventMarker")]
-      data = merge(data1$data, data2$data, by = "timestamp")
+      data = data1$data
     } else {
-      if (length(file1) > 0) {
-        data = data1$data
-      } else {
-        data = data2$data
-      }
+      data = data2$data
     }
-    colnames(data)[grep(pattern = "timestamp", x = colnames(data))] = "timestamp"
-    newName = gsub(pattern = "Sleep_Wake", replacement = "def", x =  basename(filesForThisPerson[file2]), ignore.case = TRUE)
-    newName = paste0(unlist(strsplit(newName, "[.]")) , collapse = paste0("_", deviceSN, "."))
-    newName = gsub(pattern = "xlsx", replacement = "csv", x = newName)
-    outputfile = paste0(outputPath, "/", newName)
-    write.csv(x = data, file = outputfile, row.names = FALSE)
   }
+  invisible(list(data = data, deviceSN = deviceSN))
 }
\ No newline at end of file
diff --git a/R/readPHBCount.R b/R/readPHBCount.R
index 5a1eff8..b25b0a8 100644
--- a/R/readPHBCount.R
+++ b/R/readPHBCount.R
@@ -1,12 +1,13 @@
 readPHBCount = function(filename = NULL, timeformat = "%m/%d/%Y %H:%M:%S",
                         desiredtz = "", configtz = NULL,
                         timeformatName = "timeformat") {
+  
   if (length(configtz) == 0) configtz = desiredtz
   deviceSN = NULL
   if (length(grep(pattern = "datalist", x = filename, ignore.case = TRUE)) > 0) {
     data = as.data.frame(readxl::read_excel(path = filename, 
-                                             col_types = "text", skip = 8),
-                          row.names = FALSE)
+                                            col_types = "text", skip = 8),
+                         row.names = FALSE)
     header = as.data.frame(readxl::read_excel(path = filename, 
                                               col_types = "text", n_max = 8,
                                               .name_repair = "unique_quiet"),
@@ -15,11 +16,17 @@ readPHBCount = function(filename = NULL, timeformat = "%m/%d/%Y %H:%M:%S",
     if (length(SNlocation) > 0) {
       deviceSN = unlist(strsplit(header[grep(pattern = "deviceSN", x = header)], " "))
       deviceSN = deviceSN[length(deviceSN)]
-   }
+    }
     colnames(data)[grep(pattern = "counts", x = colnames(data), ignore.case = TRUE)] = "counts"
     colnames(data)[grep(pattern = "offWrist", x = colnames(data), ignore.case = TRUE)] = "nonwear"
+    for (varname in c("counts", "steps", "nonwear")) {
+      if (varname %in% colnames(data) == FALSE) {
+        stop(paste0("Expected column ", varname, " not found in file ", filename), call. = TRUE)
+      }
+    }
     data$counts = as.numeric(data$counts)
     data$nonwear = as.numeric(data$counts)
+    data$steps = as.numeric(data$steps)
   } else {
     data = as.data.frame(readxl::read_excel(path = filename, col_types = "text", skip = 8), row.names = FALSE)
     colnames(data)[grep(pattern = "sleepWake", x = colnames(data), ignore.case = TRUE)] = "sleep"
@@ -37,7 +44,7 @@ readPHBCount = function(filename = NULL, timeformat = "%m/%d/%Y %H:%M:%S",
   # Establish starttime in the correct timezone
   if (configtz != desiredtz) {
     data$timestamp = as.POSIXct(x = as.numeric(data$timestamp), tz = desiredtz,
-                                 origin = "1970-01-01")
+                                origin = "1970-01-01")
   }
   invisible(list(data = data, deviceSN = deviceSN))
 }
\ No newline at end of file
diff --git a/inst/testfiles/def_AH1234567890_PhilipsHealthBand_000100621938.csv b/inst/testfiles/def_AH1234567890_PhilipsHealthBand_000100621938.csv
deleted file mode 100644
index b464778..0000000
--- a/inst/testfiles/def_AH1234567890_PhilipsHealthBand_000100621938.csv
+++ /dev/null
@@ -1,247 +0,0 @@
-"timestamp","counts","heartRate","respirationRate","totalEnergyExpenditure","activeEnergyExpenditure","steps","nonwear","runDuration","walkDuration","activeMinutes","restingHeartRate","heartRateRecovery","cardioFitnessIndex","vo2Max","batteryDischarge","sleepEventMarker","missingData","sleep"
-"11-05-2022 01:10:00","475","53","17","149.6173","0.0764","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:11:00","305","52","21","151.0414","0.1011","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:12:00","608","52","17","152.5025","0.1344","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:13:00","160","50","18","153.8994","0.0767","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:14:00","735","51","20","155.3830","0.1547","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:15:00","1345","52","19","156.8386","0.1294","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:16:00","144","55","17","158.5574","0.3664","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:17:00","243","54","19","159.9361","0.0603","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:18:00","171","53","17","161.3136","0.0592","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:19:00","63","54","17","162.6497","0.0219","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:20:00","761","55","18","164.0025","0.0369","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:21:00","1330","55","NaN","165.7321","0.3761","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:22:00","144","55","18","167.1846","0.1267","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:23:00","1669","52","17","168.7497","0.2281","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:24:00","356","52","18","170.2722","0.1897","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:25:00","122","51","19","171.6327","0.0439","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:26:00","121","50","19","172.9815","0.0333","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:27:00","729","51","19","174.4491","0.1403","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:28:00","1027","51","NaN","176.0438","0.2547","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:29:00","116","49","19","177.4303","0.0672","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:30:00","101","47","16","178.7790","0.0333","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:31:00","484","50","7","180.2040","0.1019","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:32:00","114","50","15","181.5673","0.0464","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:33:00","113","49","16","182.9161","0.0333","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:34:00","111","48","16","184.2648","0.0333","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:35:00","798","49","17","185.7552","0.1608","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","0"
-"11-05-2022 01:36:00","70","49","11","187.1309","0.0575","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:37:00","54","47","15","188.4611","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:38:00","54","48","15","189.7914","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:39:00","54","49","12","191.1216","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:40:00","58","48","8","192.4519","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:41:00","55","48","10","193.7821","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:42:00","56","49","13","195.1124","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:43:00","52","49","16","196.4426","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:44:00","51","48","11","197.7728","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:45:00","51","49","11","199.1031","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:46:00","50","47","15","200.4333","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:47:00","52","48","11","201.7636","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:48:00","80","47","13","203.0975","0.0200","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:49:00","46","47","14","204.4278","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:50:00","43","48","11","205.7580","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:51:00","44","47","12","207.0883","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:52:00","45","48","17","208.4185","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:53:00","49","48","17","209.7488","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:54:00","43","48","18","211.0790","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:55:00","45","48","17","212.4093","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:56:00","42","47","13","213.7395","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:57:00","175","47","15","215.0750","0.0214","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:58:00","46","47","12","216.4275","0.0367","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 01:59:00","43","47","15","217.7577","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:00:00","47","47","17","219.0880","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:01:00","45","47","17","220.4182","0.0167","0","0","0","0","0","53","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:02:00","45","47","17","221.7485","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:03:00","45","48","17","223.0787","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:04:00","1401","50","18","224.5367","0.1317","1","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
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-"11-05-2022 02:06:00","93","45","15","227.4583","0.0378","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:07:00","94","46","12","228.7889","0.0169","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
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-"11-05-2022 02:10:00","92","47","16","232.7796","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:11:00","96","47","15","234.1099","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
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-"11-05-2022 02:16:00","90","48","10","240.7698","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:17:00","90","47","12","242.1000","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:18:00","102","48","16","243.4377","0.0233","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:19:00","93","47","14","244.7679","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:20:00","94","48","15","246.0981","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:21:00","97","48","16","247.4324","0.0203","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:22:00","266","47","16","248.8068","0.0564","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
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-"11-05-2022 02:24:00","122","47","14","251.5056","0.0333","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:25:00","111","48","14","252.8543","0.0333","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:26:00","102","47","12","254.1985","0.0292","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:27:00","170","48","14","255.5318","0.0194","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:28:00","96","48","16","256.8889","0.0408","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:29:00","97","48","17","258.2225","0.0197","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:30:00","94","48","6","259.5528","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:31:00","93","48","12","260.8830","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:32:00","89","48","13","262.2133","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:33:00","1318","55","11","263.8333","0.2775","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:34:00","84","44","16","265.2198","0.0672","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:35:00","87","47","16","266.5555","0.0217","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
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-"11-05-2022 02:37:00","88","46","16","269.2161","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:38:00","329","47","16","270.5611","0.0300","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:39:00","154","52","18","271.9626","0.0808","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:40:00","84","45","15","273.3012","0.0242","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:41:00","82","45","15","274.6315","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:42:00","82","45","15","275.9617","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:43:00","85","48","15","277.2920","0.0167","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:44:00","185","49","16","278.6420","0.0344","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:45:00","101","47","14","279.9917","0.0342","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 02:46:00","110","46","15","281.3321","0.0258","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
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-"11-05-2022 05:09:00","88","43","15","478.0846","0.0300","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 05:10:00","129","45","12","479.4281","0.0286","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 05:11:00","137","43","11","480.7722","0.0292","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 05:12:00","130","43","12","482.1293","0.0408","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 05:13:00","261","43","16","483.5062","0.0586","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 05:14:00","95","43","11","484.8556","0.0339","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
-"11-05-2022 05:15:00","94","45","14","486.1861","0.0169","0","0","0","0","0","NaN","NaN","NaN","NaN","0","0","0","1"
diff --git a/man/mergePHBfilePairs.Rd b/man/mergePHBfilePairs.Rd
index e285bc3..b10f129 100644
--- a/man/mergePHBfilePairs.Rd
+++ b/man/mergePHBfilePairs.Rd
@@ -9,19 +9,16 @@
   xlsx file to csv.
 }
 \usage{
-  mergePHBfilePairs(inputPath = ".", outputPath = ".",
-                     timeformat = "\%m/\%d/\%Y \%H:\%M:\%S",
-                     desiredtz = "", configtz = NULL,
-                     timeformatName = "timeformat")
+  mergePHBfilePairs(filenames = NULL,
+                    timeformat = "\%m/\%d/\%Y \%H:\%M:\%S",
+                    desiredtz = "", configtz = NULL,
+                    timeformatName = "timeformat")
 }
 \arguments{
-  \item{inputPath}{
-    Character, file path where xlsx files are located that need to be merged. 
-    Assumption is that there is either one file starting with "Datalist_", one starting
-    with "Sleep_Wake_", or both for each recording.
-  }
-  \item{outputPath}{
-    Character, path to store the merge output
+  \item{filenames}{
+    Character vector, specifying the two filenames to be merged. 
+    Assumption is that there is one file starting with "Datalist_" and one starting
+    with "Sleep_Wake_".
   }
   \item{timeformat}{
     Character, timestemp format.
@@ -43,8 +40,7 @@
   }
 }
 \value{
-  Function does not output values. Instead it stores the merged data as file in the location
-  as specified by outputPath.
+  Merged data from the two files.
 }
 \author{
   Vincent T van Hees <v.vanhees@accelting.com>
diff --git a/tests/testthat/test_mergePHBfilePairs.R b/tests/testthat/test_mergePHBfilePairs.R
index 354585b..39c1b3b 100644
--- a/tests/testthat/test_mergePHBfilePairs.R
+++ b/tests/testthat/test_mergePHBfilePairs.R
@@ -4,32 +4,15 @@ test_that("merging of PHB files goes correctly", {
   # prepare folder with test files
   file1 = system.file("testfiles/DataList_AH1234567890_PhilipsHealthBand.xlsx", package = "GGIRread")
   file2 = system.file("testfiles/Sleep_Wake_AH1234567890_PhilipsHealthBand.xlsx", package = "GGIRread")
-  path = "./phb_test_folder"
-  if (!dir.exists(path)) {
-    dir.create(path)
-  }
-  invisible(file.copy(from = file1, to = path, overwrite = TRUE))
-  invisible(file.copy(from = file2, to = path, overwrite = TRUE))
-  
   # apply function to merge the files
-  mergePHBfilePairs(inputPath = path, outputPath = path,
+  D = mergePHBfilePairs(filenames = c(file1, file2),
                     timeformat = "%m-%d-%Y %H:%M:%S",
                     desiredtz =  "Europe/Amsterdam")
-  
-  # check whether merged file exists
-  newfiles = dir(path, full.names = TRUE)
-  newFile = newfiles[grep(pattern = "def_AH1234567890_PhilipsHealthBand_000100621938.csv", x = newfiles)]
-  expect_true(length(newFile) == 1)
-  
-  # check file content
-  data = read.csv(newFile)
-  expect_equal(nrow(data), 246)
-  expect_equal(ncol(data), 19)
-  expect_equal(sum(data$counts), 50898)
-  expect_equal(sum(data$steps), 1)
-  expect_equal(data$timestamp[1], "2022-11-05 01:10:00")
-  
-  # clean up
-  if (dir.exists(path))  unlink(path, recursive = TRUE)
+  expect_equal(nrow(D$data), 246)
+  expect_equal(ncol(D$data), 19)
+  expect_equal(sum(D$data$counts), 50898)
+  expect_equal(sum(D$data$steps), 1)
+  expect_equal(format(D$data$timestamp[1]), "2022-11-05 01:10:00")
+  expect_equal(D$deviceSN, "000100621938")
 })
  
\ No newline at end of file