feat(steps-lib): add file_exists helper function

Author: jsjoeio

ci/steps/steps-lib.sh

@@ -25,3 +25,13 @@ directory_exists() {
     echo 1
   fi
 }
+
+# Checks whether a file exists.
+file_exists() {
+  local file="${1:-}"
+  if test -f "${file:-}"; then
+    echo 0
+  else
+    echo 1
+  fi
+}

test/scripts/steps-lib.bats

@@ -23,4 +23,14 @@ source "$SCRIPT"
 @test "directory_exists should 0 if directory exists" {
   run directory_exists "$(pwd)"
   [ "$output" = 0 ]
+}
+
+@test "file_exists should 1 if file doesn't exist" {
+  run file_exists "hello-asfd.sh"
+  [ "$output" = 1 ]
+}
+
+@test "file_exists should 0 if file exists" {
+  run file_exists "steps-lib.bats"
+  [ "$output" = 0 ]
 }