Fixed test.

get-sha.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+set -eu
+
+if [[ -n $INPUT_PATH ]]; then
+  REPO_DIR="$GITHUB_WORKSPACE/$INPUT_PATH"
+
+  echo "Resolving repository path: $REPO_DIR"
+  if [[ ! -d "$REPO_DIR" ]]; then
+    echo "::error::Invalid repository path: $REPO_DIR"
+    exit 1
+  fi
+  cd "$REPO_DIR"
+fi
+
+if [[ -n "$INPUT_UNTIL" ]]; then
+  SHA=$(git log -1 --format="%H" --date=local --until="$INPUT_UNTIL")
+  if [[ -z "$SHA" ]]; then
+    echo "::warning::The SHA for date '$INPUT_UNTIL' couldn't be determined, falling back to the current sha."
+  fi
+  echo "::set-output name=sha::$SHA"
+else
+  echo "::set-output name=sha::$INPUT_SHA"
+fi