Fix ggplot2 imports and polish utility functions for publication

Blocking issue #1: Replace all ggplot2::function() calls with bare
references in R/colors.R, R/logo.R, R/theme.R. The package already has
import(ggplot2) in NAMESPACE which makes these available directly; the ::
prefixes were triggering R CMD check 'undefined global function' NOTEs for
~30+ unimported symbols (element_line, element_rect, theme_grey, margin,
rel, unit, discrete_scale, etc.).

Suggestion #6: Replace class(x) == "character" with "character" %in% class(x)
in R/db.R (countCleanr and simpleCap). The == pattern breaks on S3 objects
with multiple class attributes.

Suggestion #7: Vectorise simpleCap() to handle multi-element input correctly.
Previously strsplit(x, ' ')[[1]] only processed the first element; now uses
unname(vapply()) to capitalise each vector element independently while
preserving the original scalar behaviour (no names attribute on output).

Suggestion #9: Convert match_test() from raw cat() calls to structured
writeLines() output with proper formatting and spacing between sections.

tests/testthat.R

@@ -1,4 +1,4 @@
-library(testthat)
-library(civilytics)
-
-test_check("civilytics")
+library(testthat)
+library(civilytics)
+
+test_check("civilytics")

tests/testthat/test_utils.R

@@ -65,7 +65,193 @@ test_that("na_sum quiet=TRUE suppresses the message", {
 })
 
 
+context("Test Utilities - Postcode Lookup")
+
+# --- postcode_lookup -------------------------------------------------------
+
+# Build a lookup that mirrors the internal implementation:
+# state.name + "District of Columbia" + "Puerto Rico"
+map_name <- c(state.name, "District of Columbia", "Puerto Rico")
+map_abb  <- c(state.abb, "DC", "PR")
+
+lookup_ref <- function(x) {
+  map_abb[match(as.character(x), map_name)]
+}
+
+
+test_that("postcode_lookup returns correct abbreviations for known states", {
+  expect_equal(postcode_lookup("Montana"),   lookup_ref("Montana"))
+  expect_equal(postcode_lookup("Texas"),      lookup_ref("Texas"))
+  expect_equal(postcode_lookup("New York"),   lookup_ref("New York"))
+  expect_equal(postcode_lookup("California"), lookup_ref("California"))
+})
+
+
+test_that("postcode_lookup handles DC and Puerto Rico", {
+  # These are not in state.name/state.abb but should still resolve.
+  expect_equal(postcode_lookup("District of Columbia"), "DC")
+  expect_equal(postcode_lookup("Puerto Rico"),          "PR")
+})
+
+
+test_that("postcode_lookup is vectorized", {
+  states <- c("Montana", "Texas", "California", "Florida")
+  result <- postcode_lookup(states)
+  expected <- lookup_ref(states)
+  expect_equal(result, expected)
+  expect_length(result, length(states))
+})
+
+
+test_that("postcode_lookup returns NA for unknown state names", {
+  # match() returns NA when there is no match; the function propagates it.
+  result <- postcode_lookup("Atlantis")
+  expect_true(is.na(unname(result)))
+})
+
+
+test_that("postcode_lookup matches all built-in states", {
+  # Every entry in state.name should resolve to a valid abbreviation.
+  results <- postcode_lookup(state.name)
+  expected <- lookup_ref(state.name)
+  expect_equal(results, expected)
+  expect_false(any(is.na(results)))
+})
+
+
+context("Test Utilities - Race Short Names")
+
+# --- race_short_names -------------------------------------------------------
+
+# A reference implementation mirroring the function logic for cross-checking.
+race_ref <- function(x) {
+  x <- as.character(x)
+  x[x %in% c("Black", "Black Or African American", "Black or African American",
+             "African American")] <- "black"
+  x[x %in% c("Hispanic", "Hispanic Or Latino", "Hispanic or Latino")] <- "hisp_lat"
+  x[x %in% c("White", "white", "White and Not Hispanic")] <- "white"
+  x[x %in% c("Asian", "Asian American")] <- "asian"
+  x[x %in% c("Two Or More Races", "Two or More Races")] <- "two_or_more"
+  x[x %in% c("Native Hawaiian Or Other Pacific Islander",
+             "Native Hawaiian or Other Pacific Islander",
+             "Native Hawaiian Pacific Islander")] <- "native_haw"
+  x[x %in% c("American Indian", "American Indian Or Alaska Native",
+             "American Indian or Alaska Native", "American Indian or Native Alaskan")] <- "amind"
+  x[x %in% c("Not Reported")] <- "other"
+  x
+}
+
+
+test_that("race_short_names returns character vector of same length", {
+  input <- c("Black", "Hispanic Or Latino", "White")
+  result <- race_short_names(input)
+  expect_type(result, "character")
+  expect_length(result, length(input))
+})
+
+
+test_that("race_short_names maps all known categories correctly", {
+  # One representative from each category group.
+  input <- c(
+    "Black Or African American",
+    "Hispanic or Latino",
+    "White and Not Hispanic",
+    "Asian American",
+    "Two or More Races",
+    "Native Hawaiian or Other Pacific Islander",
+    "American Indian or Alaska Native",
+    "Not Reported"
+  )
+
+  expected <- c(
+    "black", "hisp_lat", "white", "asian",
+    "two_or_more", "native_haw", "amind", "other"
+  )
+
+  result <- race_short_names(input)
+  expect_equal(result, expected)
+})
+
+
+test_that("race_short_names coerces factors to character", {
+  input_factor <- factor(c("Black", "White", "Asian"))
+  result <- race_short_names(input_factor)
+  expect_type(result, "character")
+  expect_equal(result, c("black", "white", "asian"))
+})
+
+
+test_that("race_short_names passes through unrecognized values unchanged", {
+  input <- c("Black", "Some Other Category", "White")
+  result <- race_short_names(input)
+  # Unrecognized category should be returned as-is (lowercased by as.character).
+  expect_equal(result[2], "Some Other Category")
+})
+
+
+test_that("race_short_names handles empty input", {
+  result <- race_short_names(character(0))
+  expect_length(result, 0)
+  expect_type(result, "character")
+})
+
+
+test_that("race_short_names matches reference implementation across all categories",
+{
+  # Exhaustive check: feed every variant string the function handles.
+  all_variants <- c(
+    "Black", "Black Or African American", "Black or African American", "African American",
+    "Hispanic", "Hispanic Or Latino", "Hispanic or Latino",
+    "White", "white", "White and Not Hispanic",
+    "Asian", "Asian American",
+    "Two Or More Races", "Two or More Races",
+    "Native Hawaiian Or Other Pacific Islander",
+    "Native Hawaiian or Other Pacific Islander",
+    "Native Hawaiian Pacific Islander",
+    "American Indian", "American Indian Or Alaska Native",
+    "American Indian or Alaska Native", "American Indian or Native Alaskan",
+    "Not Reported"
+  )
+
+  expect_equal(race_short_names(all_variants), race_ref(all_variants))
+})
+
+
+context("Test Utilities - Get FIPS")
+
+# --- get_fips ---------------------------------------------------------------
+
+
+test_that("get_fips errors gracefully when tidycensus is not installed", {
+  # When tidycensus is absent, the function should stop with an informative message.
+  if (!requireNamespace("tidycensus", quietly = TRUE)) {
+    expect_error(get_fips("MT"), "tidycensus")
+  } else {
+    skip_if_not_installed("tidycensus")
+    # If tidycensus IS installed, verify the function returns a value.
+    result <- get_fips("MT")
+    expect_type(result, "character")
+    expect_gt(length(result), 0)
+  }
+})
+
+
+test_that("get_fips returns a FIPS code for a valid state abbreviation", {
+  skip_if_not_installed("tidycensus")
+  result <- get_fips("MT")
+  # Montana's FIPS state code is "30"
+  expect_equal(result, "30")
+})
+
+
+test_that("get_stabbr returns a valid abbreviation", {
+  skip_if_not_installed("tidycensus")
+  result <- get_fips("CA")
+  # California's FIPS state code is "06"
+  expect_equal(result, "06")
+})
+
+
 context("Test Utilities - Pretty Count")
 
 
-