Exercise: jq for testers

Exercises Oct 15, 2025 (Oct 15, 2025) Loading...

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A set of testing-relevant exercises to help testers use, and see the use of, jq – a tool to filter and manipulate json.

For the exercises, we'll use online jq tools. As with regex, I reckon that we don't need to be expert with jq, if we have tools to help build and explore queries. All the following tools take in json and a query, and show you the results in real time.

JQ / Playground is a page that lets you ask for jq queries in plain language, and to see their effects in real time.
JQ Play Offline is a page that shows you the results of queries more readably, and lets you work with command-line options
The JQ Playground lets you get your json from an http endpoint – and is from the makers of jq. It runs slightly less swiftly.

jq is primarily a command line tool: These pages are handy for building or testing a query, and for learning through playing, but you'll want the command line version to do work. However, jq is not always available, because it's not one of the core xNIX toolset. Its official page is jqlang.org, and

Exercise 1 –

We'll use the (generated) data below. It is an imaginary json output from a system that logs events to an events object, and logs traces to a traces object.

use keys to show the top-level keys
use traces[] to show everything in the traces array
use .traces[].traceId to show the traceIDs.
- Compare with .traces[] .traceId and .traces[] | traceId
- Compare with .traces | map(.traceId) | unique and
  [ .traces[] | .traceId ] | unique
use events[] to show everything in the events array
use .events | map(.traceId) | unique to show all the unique traceIDs in the events array.

use .traces | map({(.traceId): [.spans[].name]}) | add to show all event names for each trace.

Data

{
  "traces": [
    {
      "traceId": "123456789",
      "duration": 2000,
      "spans": [
        {
          "id": "span1",
          "name": "web_request",
          "startTime": 1634491200000,
          "endTime": 1634491201000,
          "tags": {
            "http.method": "GET",
            "http.url": "/api/users"
          }
        },
        {
          "id": "span2",
          "name": "database_query",
          "startTime": 1634491201000,
          "endTime": 1634491201500,
          "tags": {
            "db.query": "SELECT * FROM users WHERE id = 1"
          }
        },
        {
          "id": "span3",
          "name": "cache_lookup",
          "startTime": 1634491201500,
          "endTime": 1634491201800,
          "tags": {
            "cache.key": "user_profile_1"
          }
        }
      ]
    },
    {
      "traceId": "987654321",
      "duration": 3000,
      "spans": [
        {
          "id": "span1",
          "name": "web_request",
          "startTime": 1634491202000,
          "endTime": 1634491203000,
          "tags": {
            "http.method": "POST",
            "http.url": "/api/payments"
          }
        },
        {
          "id": "span2",
          "name": "payment_processing",
          "startTime": 1634491203000,
          "endTime": 1634491204000,
          "tags": {
            "payment.amount": 100.00,
            "payment.method": "credit_card"
          }
        },
        {
          "id": "span3",
          "name": "fraud_check",
          "startTime": 1634491204000,
          "endTime": 1634491204500,
          "tags": {
            "fraud.score": 10
          }
        }
      ]
    },
    {
      "traceId": "456789123",
      "duration": 1500,
      "spans": [
        {
          "id": "span1",
          "name": "mobile_request",
          "startTime": 1634491205000,
          "endTime": 1634491205500,
          "tags": {
            "http.method": "GET",
            "http.url": "/api/products"
          }
        },
        {
          "id": "span2",
          "name": "product_catalog_lookup",
          "startTime": 1634491205500,
          "endTime": 1634491206000,
          "tags": {
            "product.category": "electronics"
          }
        }
      ]
    },
    {
      "traceId": "321654987",
      "duration": 2500,
      "spans": [
        {
          "id": "span1",
          "name": "web_request",
          "startTime": 1634491207000,
          "endTime": 1634491208000,
          "tags": {
            "http.method": "POST",
            "http.url": "/api/orders"
          }
        },
        {
          "id": "span2",
          "name": "inventory_check",
          "startTime": 1634491208000,
          "endTime": 1634491208500,
          "tags": {
            "product.id": "prod123",
            "quantity": 5
          }
        },
        {
          "id": "span3",
          "name": "order_processing",
          "startTime": 1634491208500,
          "endTime": 1634491209500,
          "tags": {
            "order.id": "order456",
            "order.total": 50.00
          }
        }
      ]
    },
    {
      "traceId": "159753",
      "duration": 1000,
      "spans": [
        {
          "id": "span1",
          "name": "mobile_request",
          "startTime": 1634491210000,
          "endTime": 1634491210500,
          "tags": {
            "http.method": "GET",
            "http.url": "/api/notifications"
          }
        },
        {
          "id": "span2",
          "name": "notification_fetch",
          "startTime": 1634491210500,
          "endTime": 1634491211000,
          "tags": {
            "notification.type": "promotion",
            "notification.message": "25% off sale!"
          }
        }
      ]
    },
    {
      "traceId": "753159",
      "duration": 1800,
      "spans": [
        {
          "id": "span1",
          "name": "web_request",
          "startTime": 1634491212000,
          "endTime": 1634491212500,
          "tags": {
            "http.method": "GET",
            "http.url": "/api/profile"
          }
        },
        {
          "id": "span2",
          "name": "user_profile_fetch",
          "startTime": 1634491212500,
          "endTime": 1634491213000,
          "tags": {
            "user.id": "user123",
            "user.email": "user@example.com"
          }
        },
        {
          "id": "span3",
          "name": "settings_fetch",
          "startTime": 1634491213000,
          "endTime": 1634491213800,
          "tags": {
            "settings.theme": "dark",
            "settings.language": "en"
          }
        }
      ]
    },
    {
      "traceId": "951357",
      "duration": 2200,
      "spans": [
        {
          "id": "span1",
          "name": "mobile_request",
          "startTime": 1634491215000,
          "endTime": 1634491215500,
          "tags": {
            "http.method": "POST",
            "http.url": "/api/feedback"
          }
        },
        {
          "id": "span2",
          "name": "feedback_submit",
          "startTime": 1634491215500,
          "endTime": 1634491216000,
          "tags": {
            "feedback.rating": 4,
            "feedback.comment": "Great app, but could use more features."
          }
        },
        {
          "id": "span3",
          "name": "support_ticket_create",
          "startTime": 1634491216000,
          "endTime": 1634491217200,
          "tags": {
            "ticket.id": "ticket123",
            "ticket.priority": "medium"
          }
        }
      ]
    },
    {
      "traceId": "357951",
      "duration": 1700,
      "spans": [
        {
          "id": "span1",
          "name": "web_request",
          "startTime": 1634491218000,
          "endTime": 1634491218500,
          "tags": {
            "http.method": "GET",
            "http.url": "/api/analytics"
          }
        },
        {
          "id": "span2",
          "name": "data_aggregation",
          "startTime": 1634491218500,
          "endTime": 1634491219000,
          "tags": {
            "data.source": "user_activity",
            "data.timeframe": "last_7_days"
          }
        },
        {
          "id": "span3",
          "name": "report_generation",
          "startTime": 1634491219000,
          "endTime": 1634491219700,
          "tags": {
            "report.id": "weekly_analytics",
            "report.format": "pdf"
          }
        }
      ]
    },
    {
      "traceId": "753951",
      "duration": 2800,
      "spans": [
        {
          "id": "span1",
          "name": "mobile_request",
          "startTime": 1634491220000,
          "endTime": 1634491220500,
          "tags": {
            "http.method": "PUT",
            "http.url": "/api/settings"
          }
        },
        {
          "id": "span2",
          "name": "user_settings_update",
          "startTime": 1634491220500,
          "endTime": 1634491221000,
          "tags": {
            "setting.language": "es",
            "setting.notification_preferences": "email"
          }
        },
        {
          "id": "span3",
          "name": "email_notification",
          "startTime": 1634491221000,
          "endTime": 1634491222800,
          "tags": {
            "email.recipient": "user@example.com",
            "email.subject": "Your settings have been updated"
          }
        }
      ]
    }
  ],
  "events": [
    {
      "timestamp": 1634491200000,
      "type": "user_login",
      "data": {
        "userId": "user123",
        "ipAddress": "192.168.1.100"
      },
      "traceId": "123456789"
    },
    {
      "timestamp": 1634491201000,
      "type": "database_query",
      "data": {
        "query": "SELECT * FROM users WHERE id = 1"
      },
      "traceId": "123456789"
    },
    {
      "timestamp": 1634491201800,
      "type": "cache_hit",
      "data": {
        "cacheKey": "user_profile_1"
      },
      "traceId": "123456789"
    },
    {
      "timestamp": 1634491202000,
      "type": "payment_initiated",
      "data": {
        "paymentId": "payment123",
        "amount": 100.00
      },
      "traceId": "987654321"
    },
    {
      "timestamp": 1634491204000,
      "type": "fraud_check_complete",
      "data": {
        "fraudScore": 10
      },
      "traceId": "987654321"
    },
    {
      "timestamp": 1634491205000,
      "type": "mobile_request",
      "data": {
        "userId": "user456",
        "device": "iPhone"
      },
      "traceId": "456789123"
    },
    {
      "timestamp": 1634491205500,
      "type": "product_catalog_lookup",
      "data": {
        "productCategory": "electronics"
      },
      "traceId": "456789123"
    },
    {
      "timestamp": 1634491207000,
      "type": "order_placed",
      "data": {
        "orderId": "order456",
        "totalAmount": 50.00
      },
      "traceId": "321654987"
    },
    {
      "timestamp": 1634491208500,
      "type": "inventory_check",
      "data": {
        "productId": "prod123",
        "quantity": 5
      },
      "traceId": "321654987"
    },
    {
      "timestamp": 1634491210000,
      "type": "mobile_request",
      "data": {
        "userId": "user789",
        "device": "Android"
      },
      "traceId": "159753"
    },
    {
      "timestamp": 1634491210500,
      "type": "notification_fetched",
      "data": {
        "notificationType": "promotion",
        "notificationMessage": "25% off sale!"
      },
      "traceId": "159753"
    },
    {
      "timestamp": 1634491212000,
      "type": "user_profile_viewed",
      "data": {
        "userId": "user123",
        "userEmail": "user@example.com"
      },
      "traceId": "753159"
    },
    {
      "timestamp": 1634491213000,
      "type": "user_settings_fetched",
      "data": {
        "theme": "dark",
        "language": "en"
      },
      "traceId": "753159"
    },
    {
      "timestamp": 1634491215000,
      "type": "mobile_request",
      "data": {
        "userId": "user456",
        "device": "Android"
      },
      "traceId": "951357"
    },
    {
      "timestamp": 1634491215500,
      "type": "feedback_submitted",
      "data": {
        "rating": 4,
        "comment": "Great app, but could use more features."
      },
      "traceId": "951357"
    },
    {
      "timestamp": 1634491216000,
      "type": "support_ticket_created",
      "data": {
        "ticketId": "ticket123",
        "priority": "medium"
      },
      "traceId": "951357"
    },
    {
      "timestamp": 1634491218000,
      "type": "web_request",
      "data": {
        "userId": "user789",
        "ipAddress": "192.168.1.101"
      },
      "traceId": "357951"
    },
    {
      "timestamp": 1634491218500,
      "type": "data_aggregation",
      "data": {
        "dataSource": "user_activity",
        "timeframe": "last_7_days"
      },
      "traceId": "357951"
    },
    {
      "timestamp": 1634491219000,
      "type": "report_generated",
      "data": {
        "reportId": "weekly_analytics",
        "reportFormat": "pdf"
      },
      "traceId": "357951"
    },
    {
      "timestamp": 1634491220000,
      "type": "mobile_request",
      "data": {
        "userId": "user123",
        "device": "Android"
      },
      "traceId": "753951"
    },
    {
      "timestamp": 1634491220500,
      "type": "user_settings_updated",
      "data": {
        "language": "es",
        "notificationPreferences": "email"
      },
      "traceId": "753951"
    },
    {
      "timestamp": 1634491221000,
      "type": "email_notification_sent",
      "data": {
        "recipient": "user@example.com",
        "subject": "Your settings have been updated"
      },
      "traceId": "753951"
    }
  ]
}