Make basher-init and the include function portable

- Use local in stead of declare
- Use . in stead of source
- Add test for sh

lib/include.dash

@@ -0,0 +1 @@
+. "$BASHER_ROOT/lib/include.sh"

lib/include.sh

@@ -1,6 +1,6 @@
 include() {
-  declare package="$1"
-  declare file="$2"
+  local package="$1"
+  local file="$2"
 
   if [ -z "$package" ] || [ -z "$file" ]; then
     echo "Usage: include <package> <file>" >&2
@@ -13,7 +13,7 @@ include() {
   fi
 
   if [ -e "$BASHER_PREFIX/packages/$package/$file" ]; then
-    source "$BASHER_PREFIX/packages/$package/$file" >&2
+    . "$BASHER_PREFIX/packages/$package/$file" >&2
   else
     echo "File not found: $BASHER_PREFIX/packages/$package/$file" >&2
     return 1

libexec/basher-init

@@ -48,11 +48,11 @@ case "$shell" in
 esac
 
 if [ -e "$BASHER_ROOT/lib/include.$shell" ]; then
-  echo "source \"\$BASHER_ROOT/lib/include.$shell\""
+  echo ". \"\$BASHER_ROOT/lib/include.$shell\""
 fi
 
 if [ -e "$BASHER_ROOT/completions/basher.$shell" ]; then
-  echo "source \"\$BASHER_ROOT/completions/basher.$shell\""
+  echo ". \"\$BASHER_ROOT/completions/basher.$shell\""
 fi
 
 case "$shell" in

tests/basher-init.bats

@@ -28,7 +28,7 @@ load test_helper
 
 @test "setup include function if it exists" {
   run basher-init - bash
-  assert_line -n 4 'source "$BASHER_ROOT/lib/include.bash"'
+  assert_line -n 4 '. "$BASHER_ROOT/lib/include.bash"'
 }
 
 @test "doesn't setup include function if it doesn't exist" {
@@ -39,7 +39,7 @@ load test_helper
 @test "setup basher completions if available" {
   run basher-init - bash
   assert_success
-  assert_line -n 5 'source "$BASHER_ROOT/completions/basher.bash"'
+  assert_line -n 5 '. "$BASHER_ROOT/completions/basher.bash"'
 }
 
 @test "does not setup basher completions if not available" {
@@ -60,3 +60,14 @@ load test_helper
   assert_success
   assert_line -n 6 'fpath=("$BASHER_ROOT/cellar/completions/zsh" $fpath)'
 }
+
+hasShell() {
+  which "$1" &>>/dev/null
+}
+
+@test "is sh-compatible" {
+  hasShell sh || skip "sh was not found in path."
+  run sh -ec 'eval "$(basher init - sh)"'
+  assert_success
+}
+