diff --git a/src/assert_json.bash b/src/assert_json.bash
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+# assert_json
+# ======
+#
+# Summary: Fail if the given JSON does not match the provided jq expressions.
+#
+# See jq -e for details on how jq expressions are evaluated.
+#
+# Usage: assert_json <json> <jq_expression> [<jq_expression> ...]
+#
+# Examples:
+#   assert_json "$json" '.name == "TestProject"' '.version == "1.0.0"'
+#   assert_json "$json" '.policyConditions | length == 1'
+#
+#   # In a Bats test, using output from run command:
+#   assert_json_output '.name == "TestProject"' '.version == "1.0.0"'
+#
+#   # For arrays:
+#   assert_json "$json" '[.[] | .name] | sort == ["A", "B"]'
+#
+#   # For nested objects:
+#   assert_json "$json" '.parent.uuid == "parent-id"'
+#
+# IO:
+#   STDERR - the failed expression, on failure
+# Globals:
+#   none
+# Returns:
+#   0 - if the JSON matches all expressions
+#   1 - otherwise
+#
+assert_json() {
+  local json="$1" expression output
+  shift
+
+  for expression in "$@"
+  do
+    if ! output=$(echo "$json" | jq -e "$expression" 2>&1)
+    then
+      batslib_print_kv_single_or_multi 8 \
+      'expression' "$expression" \
+      'json'   "$json" \
+      'output' "$output" \
+      | batslib_decorate 'json does not match' \
+      | fail
+    fi
+  done
+}
+
+# refute_json
+# ========
+#
+# Summary: Fail if the given JSON matches any of the provided jq expressions.
+#
+# See jq -e for details on how jq expressions are evaluated.
+#
+# Usage: refute_json <json> <jq_expression> [<jq_expression> ...]
+#
+# Examples:
+#   refute_json "$json" '.name == "NonExistentProject"'
+#   refute_json "$json" '.policyConditions[]? | select(.uuid == "deleted-id")'
+#
+#   # In a Bats test, using output from run command:
+#   refute_json_output '.name == "NonExistentProject"'
+#
+# IO:
+#   STDERR - the failed expression, on failure
+# Globals:
+#   none
+# Returns:
+#   0 - if the JSON does not match any of the expressions
+#   1 - otherwise, also if there is a usage or compile error in jq
+#
+refute_json() {
+  local json="$1" expression output status
+  shift
+
+  for expression in "$@"
+  do
+    {
+      output=$(echo "$json" | jq -e "$expression" 2>&1)
+      status=$?
+    } || true
+
+    if (( status == 2 || status == 3 )); then
+      batslib_print_kv_single_or_multi 8 \
+      'expression' "$expression" \
+      'json'   "$json" \
+      'output' "$output" \
+      | batslib_decorate 'jq encountered a usage or compile error' \
+      | fail
+    fi
+
+    if (( status == 0 )); then
+      batslib_print_kv_single_or_multi 8 \
+      'expression' "$expression" \
+      'json'   "$json" \
+      'output' "$output" \
+      | batslib_decorate 'json matches' \
+      | fail
+    fi
+  done
+}
+
+# Usage: assert_json_output <jq_expression> [<jq_expression> ...]
+# Example: assert_json_output '.name == "TestProject"'
+assert_json_output() {
+   assert_json "${output?}" "$@"
+}
+
+# Usage: refute_json_output <jq_expression> [<jq_expression> ...]
+# Example: refute_json_output '.name == "NonExistentProject"'
+refute_json_output() {
+   refute_json "${output?}" "$@"
+}