compare_file_object

Compare RDS files using waldo for better snapshot review

Description

This comparison function loads RDS files and compares the deserialized R objects rather than raw bytes. This enables better visualization in snapshot_review() by comparing the actual object structure rather than binary serialization.

For meaningful diffs in testthat’s snapshot_review(), this function compares the R objects after deserialization using waldo::compare().

Usage

compare_file_object(old, new, print = FALSE, ...)

Arguments

old Path to the old (reference) RDS file

new Path to the new RDS file to compare

print logical whether to print waldo::compare output to R console; can become very long for complex objects like lms

…

Arguments passed on to waldo::compare

x,y: Objects to compare. x is treated as the reference object so messages describe how y is different to x.
x_arg,y_arg: Name of x and y arguments, used when generated paths to internal components. These default to "old" and "new" since it’s most natural to supply the previous value then the new value.
tolerance: If non-NULL, used as threshold for ignoring small floating point difference when comparing numeric vectors. Using any non-NULL value will cause integer and double vectors to be compared based on their values, not their types, and will ignore the difference between NaN and NA_real_.
It uses the same algorithm as all.equal(), i.e., first we generate x_diff and y_diff by subsetting x and y to look only locations with differences. Then we check that mean(abs(x_diff - y_diff)) / mean(abs(y_diff)) (or just mean(abs(x_diff - y_diff)) if y_diff is small) is less than tolerance.
max_diffs: Control the maximum number of differences shown. The default shows 10 differences when run interactively and all differences when run in CI. Set max_diffs = Inf to see all differences.
ignore_srcref: Ignore differences in function srcrefs? TRUE by default since the srcref does not change the behaviour of a function, only its printed representation.
ignore_attr: Ignore differences in specified attributes? Supply a character vector to ignore differences in named attributes. By default the “waldo_opts” attribute is listed in ignore_attr so that changes to it are not reported; if you customize ignore_attr, you will probably want to do this yourself.
For backward compatibility with all.equal(), you can also use TRUE, to all ignore differences in all attributes. This is not generally recommended as it is a blunt tool that will ignore many important functional differences.
ignore_encoding: Ignore string encoding? TRUE by default, because this is R’s default behaviour. Use FALSE when specifically concerned with the encoding, not just the value of the string.
ignore_function_env,ignore_formula_env: Ignore the environments of functions and formulas, respectively? These are provided primarily for backward compatibility with all.equal() which always ignores these environments.
list_as_map: Compare lists as if they are mappings between names and values. Concretely, this drops NULLs in both objects and sorts named components.
quote_strings: Should strings be surrounded by quotes? If FALSE, only side-by-side and line-by-line comparisons will be used, and there’s no way to distinguish between NA and “NA”.

Value

logical TRUE if objects are identical, FALSE otherwise

Examples

Code

library("snapr")

old_obj <- list(a = 1, b = 2)
new_obj <- list(a = 1, b = 3)
old_path <- tempfile(fileext = ".rds")
new_path <- tempfile(fileext = ".rds")
saveRDS(old_obj, old_path)
saveRDS(new_obj, new_path)
compare_file_object(old_path, new_path)

[1] FALSE