Exercise: jq for testers
Published on October 14, 2025
still being built...
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
jqqueries 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
keysto show the top-level keys - use
traces[]to show everything in the traces array - use
.traces[].traceIdto show the traceIDs.- Compare with
.traces[] .traceIdand.traces[] | traceId - Compare with
.traces | map(.traceId) | uniqueand
[ .traces[] | .traceId ] | unique
- Compare with
- use
events[]to show everything in the events array - use
.events | map(.traceId) | uniqueto 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": "[email protected]"
}
},
{
"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": "[email protected]",
"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": "[email protected]"
},
"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": "[email protected]",
"subject": "Your settings have been updated"
},
"traceId": "753951"
}
]
}