diff --git a/R/safety_histogram.R b/R/safety_histogram.R
new file mode 100644
index 0000000..1458e2a
--- /dev/null
+++ b/R/safety_histogram.R
@@ -0,0 +1,114 @@
+#' @title Histogram of lab data from SDTM and ADaM data
+#' @description What are the settings? description?
+#' @param data PARAM_DESCRIPTION
+#' @param settings PARAM_DESCRIPTION
+#' @param description PARAM_DESCRIPTION
+#' @return OUTPUT_DESCRIPTION
+#' @export
+#' @importFrom RColorBrewer brewer.pal
+safety_histogram <- function(data, settings, description) {
+  
+  id_col <- settings[["id_col"]]
+  value_col <- settings[["value_col"]]
+  measure_col <- settings[["measure_col"]]
+  normal_col_low <- settings[["normal_col_low"]]
+  normal_col_high <- settings[["normal_col_high"]]
+
+  unit_col <- settings[["unit_col"]]
+  low_lim <- settings[["low_lim"]]
+  up_lim <- settings[["up_lim"]]
+  # page_layout <- settings[["page_layout"]] # option doesn't work yet
+
+
+  if (!is.null(settings[["measure_values"]])) {
+    measure_selected <- settings[["measure_values"]]
+  } else {
+    measure_selected <- sort(unique(data[[measure_col]]))[1]
+  }
+
+  # prep data
+  dd <- data %>%
+    dplyr::select(one_of(c(id_col, value_col, unit_col, measure_col, normal_col_low, normal_col_high))) %>%
+    stats::setNames(., c("id_col", "value_col", "unit_col", "measure_col", "normal_col_low", "normal_col_high")) %>%
+    dplyr::filter(!is.na(value_col)) %>%
+    dplyr::filter(measure_col %in% measure_selected) %>%
+    dplyr::mutate(measure_label = paste0(measure_col, " (", unit_col, ")")) %>%
+    dplyr::group_by(measure_col) %>%
+    dplyr::mutate(bw = 3.5 * sd(value_col) / (n()^(1 / 3))) %>% # for binwidth. does nothing for now.
+    dplyr::group_by()
+
+  n_obs <- nrow(dd)
+
+  # filter for x limits
+  if (!is.null(low_lim)) {
+    low_lim_df <- data.frame(measure_col = measure_selected, low_limit = low_lim)
+    dd <- dd %>%
+      dplyr::left_join(low_lim_df, by = "measure_col") %>%
+      dplyr::filter(value_col >= low_limit)
+  }
+
+  if (!is.null(up_lim)) {
+    up_lim_df <- data.frame(measure_col = measure_selected, up_limit = up_lim)
+    dd <- dd %>%
+      dplyr::left_join(up_lim_df, by = "measure_col") %>%
+      dplyr::filter(value_col <= up_limit)
+  }
+
+  dd <- dd %>% dplyr::mutate(measure_col = factor(measure_col, levels = measure_selected))
+
+
+  # from JS code:
+  # The x-domain can be in three states:
+  # - the extent of all results
+  # - user-defined, e.g. narrower to exclude outliers
+  #
+  # Bin width is calculated with two variables:
+  # - the interquartile range
+  # - the number of results
+  #
+  # 1 When the x-domain is set to the extent of all results, the bin width should be calculated
+  #   with the unfiltered set of results, regardless of the state of the current filters.
+  #
+  # 2 Given a user-defined x-domain, the bin width should be calculated with the results that
+  #   fall inside the current domain.
+
+
+  #########################################
+  #   Create figure
+  #########################################
+
+  # get labels for fig
+
+  ylab <- "# of Observations"
+  # plot_title <- description
+  plot_title <- paste0(nrow(dd), " of ", n_obs, " participant(s) shown (", round(100 * nrow(dd) / n_obs, 1), "%)")
+
+  # color for histogram
+  col <- RColorBrewer::brewer.pal(3, "Set2")[1]
+
+  dd <- dd %>% dplyr::mutate(value_col = as.numeric(value_col))
+  # options(repr.plot.width = 1, repr.plot.height = 5) # set width and height? not sure if works
+  
+  p <- ggplot2::ggplot(data = dd) +
+    theme_bw() +
+    labs(subtitle = plot_title) +
+    theme(
+      panel.border = element_rect(fill = NA, color = "black"),
+      strip.text = element_text(size = 11),
+      strip.background = element_blank(),
+      strip.placement = "outside",
+      panel.grid.major.x = element_blank(),
+      panel.grid.minor.x = element_blank(),
+      axis.line = element_line(color = "black")
+    ) +
+    scale_x_continuous("", breaks = scales::pretty_breaks(n = 6)) +
+    scale_y_continuous(ylab, breaks = scales::pretty_breaks(n = 6), expand = expansion(mult = c(0, .1))) +
+    geom_rect(aes(xmin = normal_col_low, xmax = normal_col_high, ymin = -Inf, ymax = Inf),
+      alpha = 0.5, stat = "identity", fill = "gray90", color = "gray70"
+    ) +
+    geom_histogram(aes(x = value_col), bins = 12, fill = col, alpha = 0.6, color = col) +
+    facet_wrap(~measure_label, scales = "free", strip.position = "bottom", ncol = 3)
+
+
+  return(p)
+}
diff --git a/R_old/safety_histogram.R b/R_old/safety_histogram.R
deleted file mode 100644
index 21ff862..0000000
--- a/R_old/safety_histogram.R
+++ /dev/null
@@ -1,134 +0,0 @@
-
-library(dplyr)
-library(ggplot2)
-library(tidyr)
-library(scales)
-
-# so dplyr functions never overwritten
-select <- dplyr::select; rename <- dplyr::rename; mutate <- dplyr::mutate; 
-summarize <- dplyr::summarize; arrange <- dplyr::arrange; slice <- dplyr::slice; filter <- dplyr::filter; recode<-dplyr::recode
-
-
-safety_histogram <- function(data, settings, description){
-
-
-  id_col <- settings[["id_col"]]
-  value_col <- settings[["value_col"]]
-  measure_col <- settings[["measure_col"]]
-  normal_col_low <- settings[["normal_col_low"]]
-  normal_col_high <- settings[["normal_col_high"]]
-
-  unit_col <- settings[["unit_col"]]
-  low_lim <- settings[["low_lim"]]
-  up_lim <- settings[["up_lim"]]
-  #page_layout <- settings[["page_layout"]] # option doesn't work yet
-
-  if (!is.null(settings[["measure_values"]])){
-    measure_selected = settings[["measure_values"]]
-  } else {
-    measure_selected = sort(unique(data[[measure_col]]))[1]
-  }
-  
-
-
-  # prep data
-  dd <- data %>%
-    select(one_of(c(id_col, value_col, unit_col, measure_col, normal_col_low, normal_col_high))) %>%
-    setNames(., c("id_col","value_col","unit_col","measure_col","normal_col_low","normal_col_high")) %>%
-    filter(!is.na(value_col)) %>%
-
-    filter(measure_col%in%measure_selected) %>%
-    mutate(measure_label =  paste0(measure_col, " (", unit_col,")")) %>%
-    group_by(measure_col) %>%
-    mutate(bw = 3.5 * sd(value_col)/(n()^(1/3))) %>% # for binwidth. does nothing for now.
-    group_by()
-  
-  n_obs = nrow(dd)
-  
-  # filter for x limits
-  if (!is.null(low_lim)){
-    low_lim_df = data.frame(measure_col = measure_selected, low_limit=low_lim)
-    dd = dd %>%
-      left_join(low_lim_df, by="measure_col") %>%
-      filter(value_col>=low_limit)
-  } 
-  if (!is.null(up_lim)){
-    up_lim_df = data.frame(measure_col = measure_selected, up_limit=up_lim)
-    dd = dd %>%
-      left_join(up_lim_df, by="measure_col") %>%
-      filter(value_col<=up_limit)
-  } 
-  
-  dd = dd %>% mutate(measure_col = factor(measure_col, levels=measure_selected))
-  
-
-  # from JS code:
-  # The x-domain can be in three states:
-  # - the extent of all results
-  # - user-defined, e.g. narrower to exclude outliers
-  #
-  # Bin width is calculated with two variables:
-  # - the interquartile range
-  # - the number of results
-  #
-  # 1 When the x-domain is set to the extent of all results, the bin width should be calculated
-  #   with the unfiltered set of results, regardless of the state of the current filters.
-  #
-  # 2 Given a user-defined x-domain, the bin width should be calculated with the results that
-  #   fall inside the current domain.
-
-
-  #########################################
-  #   Create figure
-  #########################################
-
-  # get labels for fig
-
-  ylab <- "# of Observations"
-  #plot_title <- description
-  plot_title <- paste0(nrow(dd)," of ", n_obs, " participant(s) shown (", round(100*nrow(dd)/n_obs,1),"%)")
-
-  # color for histogram
-  col <- RColorBrewer::brewer.pal(3, "Set2")[1]
-
-  #options(repr.plot.width = 1, repr.plot.height = 5) # set width and height? not sure if works
-  p <- ggplot(data=dd) +
-    theme_bw() +
-    labs(subtitle=plot_title)+
-    theme(panel.border = element_rect(fill = NA, color = "black"),
-          strip.text = element_text(size=11),
-          strip.background = element_blank(),
-          strip.placement = "outside",
-          panel.grid.major.x = element_blank(),
-          panel.grid.minor.x = element_blank(),
-          axis.line = element_line(color = 'black'))+
-    scale_x_continuous("", breaks=pretty_breaks(n=6))+
-    scale_y_continuous(ylab, breaks=pretty_breaks(n=6),expand = expansion(mult = c(0, .1)))+
-    geom_rect(aes(xmin=normal_col_low , xmax=normal_col_high, ymin=-Inf, ymax=Inf),
-              alpha=0.5, stat="identity", fill = "gray90", color="gray70") +
-    geom_histogram(aes(x=value_col), bins=12, fill=col, alpha=0.6, color=col) +
-    facet_wrap(~measure_label, scales="free",strip.position="bottom",ncol=3)
-  
-  
-  return(p)
-}
-
-
-
-
-# testing
-#highlight, cmd + shift + c to uncomment chunk below
-# config <- list()
-# config[["description"]] <- "Test page"
-# config[["data"]] <- "https://raw.githubusercontent.com/RhoInc/data-library/master/data/clinical-trials/renderer-specific/adbds.csv"
-# config[["settings"]] <- safetyGraphics::generateSettings("sdtm", charts=NULL)
-# 
-# data <- read.csv(config[["data"]], stringsAsFactors = FALSE, na.strings = c("NA",""))
-# settings <- config[["settings"]]
-# settings[["unit_col"]] <- "STRESU"
-# # selections within the graphic
-# settings[["measure_values"]] = c("Bicarbonate","Chloride")  # if no  parameter selected, defaults to first (albumin)
-# settings[["low_lim"]] = c(20,90)
-# settings[["up_lim"]] = c(35,120)
-# description <- config$description
-
diff --git a/data-raw/clinical_trial_dataframe.R b/data-raw/clinical_trial_dataframe.R
deleted file mode 100644
index 6c9480c..0000000
--- a/data-raw/clinical_trial_dataframe.R
+++ /dev/null
@@ -1,9 +0,0 @@
-## code to prepare `clinical_trial_dataframe` dataset goes here
-
-clinical_trial_dataframe <- read.csv(
-    'https://raw.githubusercontent.com/RhoInc/data-library/master/data/clinical-trials/renderer-specific/adbds.csv',
-    stringsAsFactors = FALSE, 
-    na.strings = c("NA","")
-  )
-
-usethis::use_data(clinical_trial_dataframe, overwrite = TRUE)
diff --git a/data/clinical_trial_dataframe.rda b/data/clinical_trial_dataframe.rda
deleted file mode 100644
index 7064052..0000000
Binary files a/data/clinical_trial_dataframe.rda and /dev/null differ
diff --git a/examples/test_safety_histogram.R b/examples/test_safety_histogram.R
deleted file mode 100644
index 76100d0..0000000
--- a/examples/test_safety_histogram.R
+++ /dev/null
@@ -1,15 +0,0 @@
-
-config <- list()
-config[["description"]] <- "Test page"
-config[["data"]] <- "https://raw.githubusercontent.com/RhoInc/data-library/master/data/clinical-trials/renderer-specific/adbds.csv"
-config[["settings"]] <- safetyGraphics::generateSettings("sdtm", charts="safetyhistogram")
-
-data <- read.csv('https://raw.githubusercontent.com/RhoInc/data-library/master/data/clinical-trials/renderer-specific/adbds.csv',
-                 stringsAsFactors = FALSE, na.strings = c("NA",""))
-settings <- config[["settings"]]
-settings[["unit_col"]] <- "STRESU"
-description <- config[["description"]]
-
-source("R/safety_histogram.R")
-p <- safety_histogram(data=data, settings=settings, description=config$description)
-ggsave("examples/test_safety_histogram.png", plot=p, dpi=300)
diff --git a/examples/test_safety_histogram.png b/examples/test_safety_histogram.png
deleted file mode 100644
index bffa2a8..0000000
Binary files a/examples/test_safety_histogram.png and /dev/null differ
diff --git a/tests/testthat/test-safety_histogram.R b/tests/testthat/test-safety_histogram.R
new file mode 100644
index 0000000..ec13156
--- /dev/null
+++ b/tests/testthat/test-safety_histogram.R
@@ -0,0 +1,25 @@
+
+# test histogram is made correctly ----------------------------------------
+
+test_that("Safety histogram is created properly", {
+  
+  
+  histogram_settings <- list(
+    id_col="USUBJID", # DONE
+    value_col="LBORRES", # DONE
+    measure_col="LBTEST", # DONE
+    visit_col="VISIT", # DONE
+    studyday_col="LBDY", # DONE
+    normal_col_low="LBORNRLO", # DONE
+    normal_col_high="LBORNRHI", # DONE
+    visitn_col="VISITNUM", # DONE
+    unit_col="LBORRESU", # DONE,
+    measure_values = "Phosphate"
+    # measure_values = "Albumin" 
+  )
+  
+  output_histogram <- safety_histogram(data = safetyData::sdtm_lb, settings = histogram_settings)
+  
+  expect_is(output_histogram, "ggplot")
+  
+})