diff --git a/tests/testthat/helper-functions.R b/tests/testthat/helper-functions.R
new file mode 100644
index 00000000..f1cd0788
--- /dev/null
+++ b/tests/testthat/helper-functions.R
@@ -0,0 +1,74 @@
+library(testthat)
+equal_with_tolerance <- function(tolerance = 1e-2) {
+  function(a, b) {
+    c <- base::mapply(function(x, y) {
+      if (is.na(x) && is.na(y)) {
+        return(0)
+      } else if (is.na(x) || is.na(y)) {
+        return(tolerance + 1)
+      } else {
+        return(abs(x - y))
+      }
+    }, a, b)
+    return(base::all(c < tolerance))
+  }
+}
+equal_exact <- function() {
+  function(a, b) {
+    x <- base::mapply(function(x, y) x == y || (is.na(x) && is.na(y)), a, b)
+    return(base::all(x))
+  }
+}
+
+expect_similar_dataframes <- function(
+    name,
+    actual_df,
+    column_comparation_functions) {
+  actual_df_filename <- file.path(tempdir(), paste(name, "csv", sep = "."))
+  write.csv(actual_df, actual_df_filename)
+  compare_fun <- function(expected_df_filename, actual_df_filename) {
+    return(compare_dataframes(
+      expected_df_filename,
+      actual_df_filename,
+      column_comparation_functions
+    ))
+  }
+  expect_snapshot_file(actual_df_filename, compare = compare_fun)
+}
+
+
+compare_dataframes <- function(
+    expected_df_filename,
+    actual_df_filename,
+    column_comparation_functions) {
+  expected_df <- read.csv(expected_df_filename)
+  actual_df <- read.csv(actual_df_filename)
+
+  all_columns_ok <- TRUE
+  for (col in base::names(column_comparation_functions)) {
+    if (col %in% colnames(expected_df) && col %in% colnames(actual_df)) {
+      compare_function <- column_comparation_functions[[col]]
+      col_ok <- compare_function(expected_df[[col]], actual_df[[col]])
+      if (!col_ok) {
+        cat(
+          "Column",
+          col,
+          "differs ",
+          expected_df[[col]],
+          "!=",
+          actual_df[[col]],
+          "\n"
+        )
+      }
+      all_columns_ok <- all_columns_ok && col_ok
+    } else {
+      if (!(col %in% colnames(expected_df))) {
+        cat("Column", col, "not in first dataframe")
+      }
+      if (!(col %in% colnames(expected_df))) {
+        cat("Column", col, "not in second dataframe")
+      }
+    }
+  }
+  return(all_columns_ok)
+}