diff --git a/.github/workflows/test-coverage.yaml b/.github/workflows/test-coverage.yaml
new file mode 100644
index 0000000..74a685d
--- /dev/null
+++ b/.github/workflows/test-coverage.yaml
@@ -0,0 +1,57 @@
+# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
+# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+name: test-coverage.yaml
+
+permissions: read-all
+
+jobs:
+  test-coverage:
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: r-lib/actions/setup-r@v2
+
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: any::covr, any::xml2
+          needs: coverage
+
+      - name: Test coverage
+        run: |
+          cov <- covr::package_coverage(
+            quiet = FALSE,
+            clean = FALSE,
+            install_path = file.path(normalizePath(Sys.getenv("RUNNER_TEMP"), winslash = "/"), "package")
+          )
+          covr::to_cobertura(cov)
+        shell: Rscript {0}
+
+      - uses: codecov/codecov-action@v7
+        with:
+          fail_ci_if_error: ${{ github.event_name != 'pull_request' && true || false }}
+          files: ./cobertura.xml
+          plugins: noop
+          disable_search: true
+
+      - name: Show testthat output
+        if: always()
+        run: |
+          find '${{ runner.temp }}/package' -name 'testthat.Rout*' -exec cat '{}' \; || true
+        shell: bash
+
+      - name: Upload test results
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-test-failures
+          path: ${{ runner.temp }}/package
diff --git a/DESCRIPTION b/DESCRIPTION
index dc0124c..19ae481 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: codriver
 Title: Context-Aware AI Assistant for 'RStudio'
-Version: 1.0.0
+Version: 1.0.0.9000
 Authors@R: person("S.A.", "van der Wulp", , "vdwulp@gmail.com", role = c("aut", "cre", "cph"))
 Description: A context-aware AI assistant for 'RStudio' that works directly in
     the source editor without switching context or opening a separate chat
diff --git a/NEWS.md b/NEWS.md
index 0f8cb25..244f263 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 # codriver (development version)
 
+* Increased test coverage to 100%.
+
 # codriver 1.0.0
 
 * Initial CRAN submission.
diff --git a/R/zzz.R b/R/zzz.R
index 117c3cc..ecc0a3b 100644
--- a/R/zzz.R
+++ b/R/zzz.R
@@ -3,9 +3,13 @@
 
 #' @noRd
 .onLoad <- function(libname, pkgname) {
+  # nocov start - no test coverage for this function
+
   # Create a private environment each time the package is loaded
   .codriver_env <<- new.env(parent = emptyenv())
 
   # Initialize config slot
   .codriver_env$config  <- read_config()
+
+  # nocov end
 }
diff --git a/README.md b/README.md
index ffbd414..b6b65e2 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,7 @@
 [![CRAN status](https://www.r-pkg.org/badges/version/codriver)](https://CRAN.R-project.org/package=codriver)
 [![License: MIT](https://img.shields.io/badge/license-MIT-green.svg)](https://github.com/vdwulp/codriver/blob/master/LICENSE.md)
 [![R-CMD-check](https://github.com/vdwulp/codriver/actions/workflows/R-CMD-check.yaml/badge.svg)](https://github.com/vdwulp/codriver/actions/workflows/R-CMD-check.yaml)
+[![Codecov test coverage](https://codecov.io/gh/vdwulp/codriver/branch/main/graph/badge.svg)](https://app.codecov.io/gh/vdwulp/codriver/tree/main)
 <!-- badges: end -->
 
 *A context-aware AI assistant for RStudio that is literally at your fingertips.*
diff --git a/tests/testthat/test-build_prompt.R b/tests/testthat/test-build_prompt.R
index ad2928b..10aa25c 100644
--- a/tests/testthat/test-build_prompt.R
+++ b/tests/testthat/test-build_prompt.R
@@ -352,6 +352,33 @@ test_that("build_prompt - preamble reports no library calls when none present",
 })
 
 
+
+# ── Line truncation ───────────────────────────────────────────────────────────
+
+test_that("build_prompt - before: truncates to n_lines from end when context exceeds limit", {
+  # 35 lines > 30-line limit; only last 30 should appear in Code window
+  ctx    <- make_context(c(paste0("line", seq_len(35L)), ""))
+  action <- make_action("continue", position = pos(36L, 1L))
+  bp_mocks({
+    result <- bp(ctx, action)
+    expect_match(result$user, "line35")
+    expect_false(grepl("line1\\b", result$user))
+  })
+})
+
+test_that("build_prompt - after: truncates to n_lines from start when context exceeds limit", {
+  # position at line 1; 15 lines after > 10-line limit for after()
+  ctx    <- make_context(c("x <- 1", paste0("after", seq_len(15L))))
+  action <- make_action("edit", text = "x <- 1", position = pos(1L, 7L),
+                        range = rng(1L, 1L, 1L, 7L))
+  bp_mocks({
+    result <- bp(ctx, action)
+    expect_match(result$user, "after1")
+    expect_false(grepl("after15", result$user))
+  })
+})
+
+
 # ── Block formatting ──────────────────────────────────────────────────────────
 
 test_that("build_prompt - blocks use START/END delimiters", {
diff --git a/tests/testthat/test-build_prompt_workspace.R b/tests/testthat/test-build_prompt_workspace.R
index b40e522..a5d07c7 100644
--- a/tests/testthat/test-build_prompt_workspace.R
+++ b/tests/testthat/test-build_prompt_workspace.R
@@ -329,7 +329,7 @@ test_that("describe_columns - detects suffix pattern when columns share a last t
 
 test_that("describe_columns - suffix owned by a single prefix group is discarded", {
   # All _usd columns start with "amt" -> single prefix owner -> discard
-  result <- dc(c("amt_usd_a", "amt_usd_b", "other_eur"))
+  result <- dc(c("amt_a_usd", "amt_b_usd", "other_eur"))
   expect_false(grepl("\\*_usd", result))
 })
 
diff --git a/tests/testthat/test-configure.R b/tests/testthat/test-configure.R
index 1e8c5e9..c8dd23a 100644
--- a/tests/testthat/test-configure.R
+++ b/tests/testthat/test-configure.R
@@ -308,3 +308,26 @@ test_that("is_shortcut_registered - returns empty string when codriver::codriver
   local_mocked_bindings(rstudio_config_path = function(...) tmp, .package = "codriver")
   expect_equal(is_shortcut_registered(), "")
 })
+
+
+# ── register_shortcut ─────────────────────────────────────────────────────────
+
+test_that("register_shortcut - returns TRUE when shortcut is registered after call", {
+  with_mocked_bindings(
+    use_rstudio_keyboard_shortcut = function(...) invisible(NULL),
+    is_shortcut_registered = function() "Ctrl+Shift+P",
+    {
+      expect_true(register_shortcut("Ctrl+Shift+P"))
+    }
+  )
+})
+
+test_that("register_shortcut - returns FALSE when shortcut is not registered after call", {
+  with_mocked_bindings(
+    use_rstudio_keyboard_shortcut = function(...) invisible(NULL),
+    is_shortcut_registered = function() NULL,
+    {
+      expect_false(register_shortcut("Ctrl+Shift+P"))
+    }
+  )
+})
diff --git a/tests/testthat/test-resolve_action.R b/tests/testthat/test-resolve_action.R
index cbd15aa..9707f00 100644
--- a/tests/testthat/test-resolve_action.R
+++ b/tests/testthat/test-resolve_action.R
@@ -99,6 +99,10 @@ test_that("scan_lines - ignores # inside raw string with padding r\"-(...)- \"",
   expect_equal(scan_col(c('x <- r"-(# not a comment)-"'), 1L), -1L)
 })
 
+test_that("scan_lines - ignores # inside raw string with multi-dash padding", {
+  expect_equal(scan_col(c('x <- r"---(# not a comment)---"'), 1L), -1L)
+})
+
 test_that("scan_lines - detects comment after closed raw string", {
   expect_equal(scan_col(c('x <- r"(text)" # comment'), 1L), 16L)
 })
@@ -345,6 +349,12 @@ test_that("resolve_action - multi-line selection ending at col 1 trims trailing
   expect_false(endsWith(result$text, "\n"))
 })
 
+test_that("resolve_action - multi-line code selection where anchor is start row with inline comment -> comment", {
+  ctx    <- make_selection_context(c("x <- 1 # old", "  "), 1L, 8L, 2L, 2L)
+  result <- ra(ctx)
+  expect_equal(result$mode, "comment")
+})
+
 test_that("resolve_action - multi-line comment selection -> generate from contiguous block", {
   ctx    <- make_selection_context(c("# line one", "# line two", "x <- 1"), 1L, 1L, 2L, 11L)
   result <- ra(ctx)
@@ -352,6 +362,15 @@ test_that("resolve_action - multi-line comment selection -> generate from contig
   expect_equal(result$text, "line one\nline two")
 })
 
+test_that("resolve_action - multi-line comment selection with non-comment row above anchor stops block at code row", {
+  # row 1 is code, rows 2-3 are comments; selection covers all three
+  # anchor = row 3 (comment), walk up hits row 1 (code) -> break -> block is rows 2-3 only
+  ctx    <- make_selection_context(c("x <- 1", "# line one", "# line two"), 1L, 1L, 3L, 11L)
+  result <- ra(ctx)
+  expect_equal(result$mode, "generate")
+  expect_equal(result$text, "line one\nline two")
+})
+
 test_that("resolve_action - multi-line selection with only whitespace -> continue", {
   ctx    <- make_selection_context(c("", ""), 1L, 1L, 2L, 1L)
   result <- ra(ctx)
@@ -362,6 +381,32 @@ test_that("resolve_action - multi-line whitespace selection with comment start l
   ctx    <- make_selection_context(c("# instruction", "  ", "  "), 1L, 1L, 3L, 1L)
   result <- ra(ctx)
   expect_equal(result$mode, "generate")
+  expect_equal(result$text, "instruction")
+})
+
+test_that("resolve_action - multi-line whitespace selection with comment start line, anchor in whitespace -> generate", {
+  ctx    <- make_selection_context(c("# instruction   ", "  "), 1L, 15L, 2L, 2L)
+  result <- ra(ctx)
+  expect_equal(result$mode, "generate")
+  expect_equal(result$text, "instruction")
+})
+
+test_that("resolve_action - multi-line whitespace selection with code start line, anchor at comment column -> comment", {
+  ctx    <- make_selection_context(c("x <- 1 # note", "  "), 1L, 8L, 2L, 2L)
+  result <- ra(ctx)
+  expect_equal(result$mode, "comment")
+})
+
+test_that("resolve_action - multi-line whitespace selection with code start line, anchor past inline comment -> comment", {
+  ctx    <- make_selection_context(c("x <- 1 # note   ", "  "), 1L, 15L, 2L, 2L)
+  result <- ra(ctx)
+  expect_equal(result$mode, "comment")
+})
+
+test_that("resolve_action - multi-line whitespace selection with code start line -> complete", {
+  ctx    <- make_selection_context(c("x <- 1     ", "  "), 1L, 8L, 2L, 2L)
+  result <- ra(ctx)
+  expect_equal(result$mode, "complete")
 })