Add additional tests

[matthewmcneely]

Description

This PR adds additional tests for geo types and client pool operation under load

Checklist

• Code compiles correctly and linting passes locally
• Tests added for new functionality, or regression tests for bug fixes added as applicable

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[Copilot]

Pull Request Overview

This PR standardizes licensing headers across the codebase, extends raw query support with optional variables, adds verbose logging for engine queries, and introduces new geo-type tests along with more comprehensive client pool tests under load.

• Updated license headers to use SPDX format in tests, examples, and API files
• Added GeoLocation support and geo-filter test cases in query_test.go
• Changed Client.QueryRaw signature/implementation to accept a vars map and updated related calls
• Enhanced engine logging for queries and extended client pool tests (concurrency and stress)

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
util_test.go	Updated license header to SPDX
update_test.go	Updated license header to SPDX
unit_test/conn_test.go	Updated license header to SPDX
query_test.go	Defined GeoLocation, added geo-filter tests, updated raw calls
insert_test.go	Updated license header to SPDX
examples/readme/main.go	Updated license header to SPDX
examples/basic/main.go	Updated license header to SPDX
engine.go	Added logger.V(2).Info for namespace queries
delete_test.go	Updated license header to SPDX
cmd/query/main.go	Passed nil for new vars param in QueryRaw call
client_test.go	Added client-pool concurrency & stress tests
client.go	Extended QueryRaw to accept vars, switched to Context txn
api/types_test.go	Updated license header to SPDX
api/types.go	Updated license header to SPDX
admin_test.go	Updated license header to SPDX

Comments suppressed due to low confidence (3)

client.go:353

• [nitpick] The local variable client shadows the receiver c, which can be confusing. Consider renaming the pooled connection to something like dgraphClient or conn.

client, cleanup, err := c.pool.get(client)

query_test.go:67

• [nitpick] The field name Coord is less descriptive than Coordinates and already maps to the JSON tag coordinates. Renaming to Coordinates would improve clarity.

Coord []float64 `json:"coordinates"`

query_test.go:236

• Currently this new test exercises only the Dgraph client mode. Consider adding a similar QueryRawWithVars test for the engine-backed client (e.g., using file:// URI) to ensure variable binding works in both modes.

t.Run("QueryRawWithVars", func(t *testing.T) {