Make wrapper work for simple usecase

test/runner

@@ -2,7 +2,7 @@
 
 try() {
   output=$(mktemp -d)
-  "$@" > "$output/stdout" 2> "$output/stderr"
+  PATH="$fake_path:$PATH" "$@" > "$output/stdout" 2> "$output/stderr"
   EXIT_CODE=$?
   STDOUT=$(<"$output/stdout")
   STDERR=$(<"$output/stderr")
@@ -14,12 +14,14 @@ setUp() {
   export TMPDIR="$PWD/.generated"
   export-repo-root
   move-to-working-directory
+  create-fake-path
 }
 
 tearDown() {
   [ "${_shunit_test_:=}" = '' ] && return 0
 
   clean-up-working-directory
+  clean-up-fake-path
 
   if [ "${__shunit_testSuccess:?}" != 0 ]; then
     output-outputs
@@ -39,11 +41,20 @@ move-to-working-directory() {
   cd $working_dir
 }
 
+create-fake-path() {
+  fake_path=$(mktemp -d)
+  invokations=$(mktemp -d)
+}
+
 clean-up-working-directory() {
   cd $original_dir
   rm -rf $working_dir
 }
 
+clean-up-fake-path() {
+  rm -rf $fake_path $invokations
+}
+
 output-outputs() {
   (
   bold '*******Test failed********'
@@ -61,6 +72,39 @@ bold() {
   echo -e "\033[0m"
 }
 
+mock() {
+  command="$1"; shift
+  [[ -n "$1" ]] && output="$1"; shift
+
+  if ! [[ -f $fake_path/$command ]]; then
+    echo 'echo "$@" >> '$invokations/$command > $fake_path/$command
+    chmod +x $fake_path/$command
+  fi
+
+  if [[ -n "$output" ]]; then
+    echo "echo '$output'" >> $fake_path/$command
+  fi
+}
+
+assertCalledWithArguments() {
+  if ! [[ -f $invokations/$1 ]]; then
+    fail "$1 never invoked"
+    return 1
+  fi
+  if ! assertContains "$1 not invoked with expected arguments:" "$(<$invokations/$1)" "$2"; then
+    bold Actual invokations:
+    cat "$invokations/$1"
+    return 1
+  fi
+}
+
+assertNotCalled() {
+  if [[ -f $invokations/$1 ]]; then
+    fail "$1 has been invoked"
+    return 1
+  fi
+}
+
 SHUNIT_PATH=./.generated/shunit2-2.1.8/shunit2
 if [ ! -f $SHUNIT_PATH ]; then (
   mkdir -p .generated