diff --git a/Justfile b/Justfile
index 32d4da5..3c62a73 100644
--- a/Justfile
+++ b/Justfile
@@ -1,74 +1,104 @@
-all: build test xtests
-all-release: build-release test-release xtests-release
+all: build test
+all-release: build-release test-release
 
 
-# compiles the exa binary
+#----------#
+# building #
+#----------#
+
+# compile the exa binary
 @build:
     cargo build
 
-# compiles the exa binary (in release mode)
+# compile the exa binary (in release mode)
 @build-release:
     cargo build --release --verbose
 
-# compiles the exa binary with every combination of feature flags
-@build-features:
-    cargo hack build --feature-powerset
+# produce an HTML chart of compilation timings
+@build-time:
+    cargo +nightly clean
+    cargo +nightly build -Z timings
+
+# check that the exa binary can compile
+@check:
+    cargo check
 
 
-# runs unit tests
+#---------------#
+# running tests #
+#---------------#
+
+# run unit tests
 @test:
-    cargo test --all -- --quiet
+    cargo test --workspace -- --quiet
 
-# runs unit tests (in release mode)
+# run unit tests (in release mode)
 @test-release:
-    cargo test --release --all --verbose
-
-# runs unit tests with every combination of feature flags
-@test-features:
-    cargo hack test --feature-powerset -- --quiet
+    cargo test --workspace --release --verbose
 
 
-# runs extended tests
+#------------------------#
+# running extended tests #
+#------------------------#
+
+# run extended tests
 @xtests:
     xtests/run.sh
 
-# runs extended tests (using the release mode exa)
+# run extended tests (using the release mode exa)
 @xtests-release:
     xtests/run.sh --release
 
+# display the number of extended tests that get run
+@count-xtests:
+    grep -F '[[cmd]]' -R xtests | wc -l
 
-# lints the code
+
+#-----------------------#
+# code quality and misc #
+#-----------------------#
+
+# lint the code
 @clippy:
     touch src/main.rs
     cargo clippy
 
-# updates dependency versions, and checks for outdated ones
+# update dependency versions, and checks for outdated ones
 @update-deps:
     cargo update
     command -v cargo-outdated >/dev/null || (echo "cargo-outdated not installed" && exit 1)
     cargo outdated
 
-# lists unused dependencies
+# list unused dependencies
 @unused-deps:
     command -v cargo-udeps >/dev/null || (echo "cargo-udeps not installed" && exit 1)
     cargo +nightly udeps
 
-# prints versions of the necessary build tools
+# check that every combination of feature flags is successful
+@check-features:
+    command -v cargo-hack >/dev/null || (echo "cargo-hack not installed" && exit 1)
+    cargo hack check --feature-powerset
+
+# print versions of the necessary build tools
 @versions:
     rustc --version
     cargo --version
 
 
-# builds the man pages
+#---------------#
+# documentation #
+#---------------#
+
+# build the man pages
 @man:
     mkdir -p "${CARGO_TARGET_DIR:-target}/man"
     pandoc --standalone -f markdown -t man man/exa.1.md        > "${CARGO_TARGET_DIR:-target}/man/exa.1"
     pandoc --standalone -f markdown -t man man/exa_colors.5.md > "${CARGO_TARGET_DIR:-target}/man/exa_colors.5"
 
-# builds and previews the main man page (exa.1)
+# build and preview the main man page (exa.1)
 @man-1-preview: man
     man "${CARGO_TARGET_DIR:-target}/man/exa.1"
 
-# builds and previews the colour configuration man page (exa_colors.5)
+# build and preview the colour configuration man page (exa_colors.5)
 @man-5-preview: man
     man "${CARGO_TARGET_DIR:-target}/man/exa_colors.5"
diff --git a/xtests/run.sh b/xtests/run.sh
index 83682d1..bbae83b 100755
--- a/xtests/run.sh
+++ b/xtests/run.sh
@@ -7,6 +7,11 @@ case "$1" in
   *)           exa_binary="$HOME/target/debug/exa" ;;
 esac
 
+if [ ! -e /vagrant ]; then
+  echo "The extended tests must be run on the Vagrant machine."
+  exit 1
+fi
+
 if [ ! -f "$exa_binary" ]; then
   echo "exa binary ($exa_binary) does not exist"
   if [ "$1" != "--release" ]; then echo -e "create it first with \033[1;32mbuild-exa\033[0m or \033[1;32mb\033[0m"; fi