test: Incorporate gomega matchers

[islamaliev]

Relevant issue(s)

Resolves #3189

Description

Replace the Validator interface with gomega.OmegaMatcher that doesn't assert directly, but instead matches the actual value against the expected value and returns bool as a result. This allows different matchers to be combined.

Moreover, gomega provides a number of very handy matchers that we can use.

[islamaliev]

These are examples of how failed tests look:

--- FAIL: TestQueryCommitsBranchables_SyncsAcrossPeerConnection (0.44s)
    /Users/islam/dev/sourcenetwork/defradb/tests/integration/query/commits/branchables/utils.go:2085: 
        	Error Trace:	/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:2085
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:2036
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:2050
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:1979
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:1818
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:397
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:272
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:220
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/query/commits/branchables/peer_test.go:94
        	Error:      	Expected Cid value to be unique, but ids "age2" and "age" point to the same cid: bafyreidywfgum7d5ceglywjsomjbwaf5qn4zxomye53xdet6acqj77haba
        	Test:       	TestQueryCommitsBranchables_SyncsAcrossPeerConnection
        	Messages:   	Path: commits[3].links[0].cid

--- FAIL: TestP2PWithSingleDocumentUpdatePerNode (0.54s)
    /Users/islam/dev/sourcenetwork/defradb/tests/integration/net/simple/peer/utils.go:2085: 
        	Error Trace:	/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:2085
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:2036
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:1979
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:1818
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:397
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:272
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/utils.go:220
        	            				/Users/islam/dev/sourcenetwork/defradb/tests/integration/net/simple/peer/with_update_test.go:186
        	Error:      	Expected
        	            		45
        	            	to be one of
        	            		[450 600]
        	Test:       	TestP2PWithSingleDocumentUpdatePerNode
        	Messages:   	Path: Users[0].Age

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.49%. Comparing base (fddff39) to head (93665ea).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3489      +/-   ##
===========================================
+ Coverage    78.48%   78.49%   +0.01%     
===========================================
  Files          397      397              
  Lines        37599    37599              
===========================================
+ Hits         29506    29510       +4     
+ Misses        6399     6397       -2     
+ Partials      1694     1692       -2     

Flag	Coverage Δ
all-tests	78.49% <ø> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

see 13 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update fddff39...93665ea. Read the comment docs.

[fredcarle]

LGTM. Looking forward to see how this might impact our tests in the future.