Assert error shown when curl, wget, & aria2c are unavailable

Closes rbenv#1234

bin/ruby-build

@@ -316,7 +316,7 @@ detect_http_client() {
       return
     fi
   done
-  echo "error: please install \`aria2c\`, \`curl\`, or \`wget\` and try again" >&2
+  echo "error: install \`curl\`, \`wget\`, or \`aria2c\` to download packages" >&2
   return 1
 }
 

test/fetch.bats

@@ -18,6 +18,15 @@ setup() {
   assert_output_contains "error: failed to download package-1.0.0.tar.gz"
 }
 
+@test "no download tool" {
+  export -n RUBY_BUILD_HTTP_CLIENT
+  clean_path="$(remove_commands_from_path curl wget aria2c)"
+
+  PATH="$clean_path" install_fixture definitions/without-checksum
+  assert_failure
+  assert_output_contains 'error: install `curl`, `wget`, or `aria2c` to download packages'
+}
+
 @test "using aria2c if available" {
   export RUBY_BUILD_ARIA2_OPTS=
   export -n RUBY_BUILD_HTTP_CLIENT

test/test_helper.bash

@@ -14,6 +14,19 @@ if [ "$FIXTURE_ROOT" != "$BATS_TEST_DIRNAME/fixtures" ]; then
   export PATH
 fi
 
+remove_commands_from_path() {
+  local path cmd
+  local paths=( $(command -v "$@" | sed 's!/[^/]*$!!' | sort -u) )
+  local NEWPATH=":$PATH:"
+  for path in "${paths[@]}"; do
+    local tmp_path="$(mktemp -d "$TMP/path.XXXXX")"
+    ln -fs "$path"/* "$tmp_path/"
+    for cmd; do rm -f "$tmp_path/$cmd"; done
+    NEWPATH="${NEWPATH/:$path:/:$tmp_path:}"
+  done
+  echo "${NEWPATH#:}"
+}
+
 teardown() {
   rm -fr "${TMP:?}"/*
 }