env: implement builtin env

test.sh

@@ -305,6 +305,7 @@ EOF
 
 EXTRAENV=-i
 when_run <<EOF "export with strange inputs"
+export ENV=$(which env)
 export PATH=$PATH
 export var
 echo status=\$?
@@ -312,7 +313,7 @@ echo var=[\$var]
 export blue=
 echo status=\$?
 echo blue=[\$blue]
-env -u PATH env
+\$ENV -u PATH -u ENV env
 EOF
 expecting <<EOF
 status=0
@@ -451,6 +452,36 @@ hi -n hello
 goodbye
 EOF
 
+EXTRAENV="-i"
+when_run <<EOF "env works"
+echo this should be empty:
+env
+echo
+export var=VALUE hi=hello bye=goodbye
+echo this contains some values
+env
+EOF
+expecting <<EOF
+this should be empty:
+
+this contains some values
+var=VALUE
+hi=hello
+bye=goodbye
+EOF
+
+EXTRAENV="-i"
+when_run <<EOF "env ignores additional arguments"
+export var=VALUE hi=hello bye=goodbye
+env -i name="The Other" ls
+EOF
+expecting <<EOF
+minishell: env: ignoring arguments
+var=VALUE
+hi=hello
+bye=goodbye
+EOF
+
 when_run <<EOF "quoted parentheses are not operators"
 echo unclosed '('
 EOF