Match has_one direction before deleting rel

[bobmazanec]

Fixes #1650

When relationship_corresponding_rel matches on the rel class name,
it stops on the first match, ignoring the direction parameter.

When target_class represents the to_node, direction is :in.

When the relationship is a has_one/has_many between a pair
of nodes of the same class, the match could find and return
the to_node's :out association first, causing
delete_reverse_has_one_relationship to delete it.

Checking the direction first prevents that.

Sadly, I worked through #1660 before seeing #1650 and that I had reached the same basic conclusion, only factoring the fix slightly differently than the OP proposed.

Test runs

I added 4 examples—2 simply show that the 'setup' in the 'real' examples works as expected. The other 2 (really the same example but under both creates_unique :all and creates_unique :none) show the problem.

Before

1907 examples, 0 failures, 5 pending

After

Without the fix

[...]
1) between nodes of the same class with creates_unique(:all) given (gen1)-->(gen0) #create (gen2)-->(gen1) adds a new node and relationsihp without affecting (gen1)-->(gen0)
     Failure/Error: expect(@gen1.parent).to(be_present, "gen1 lost its parent")
       gen1 lost its parent
     Shared Example Group: :creating_gen2 called from ./spec/e2e/relationship_spec.rb:650
     # ./spec/e2e/relationship_spec.rb:636:in `block (5 levels) in <top (required)>'

  2) between nodes of the same class with creates_unique(:none) given (gen1)-->(gen0) #create (gen2)-->(gen1) adds a new node and relationsihp without affecting (gen1)-->(gen0)
     Failure/Error: expect(@gen1.parent).to(be_present, "gen1 lost its parent")
       gen1 lost its parent
     Shared Example Group: :creating_gen2 called from ./spec/e2e/relationship_spec.rb:650
     # ./spec/e2e/relationship_spec.rb:636:in `block (5 levels) in <top (required)>'

1911 examples, 2 failures, 5 pending

With the fix

1911 examples, 0 failures, 5 pending

[codecov-commenter]

Codecov Report

Merging #1662 (1ccef51) into 10 (95f249d) will increase coverage by 0.23%.
The diff coverage is 100.00%.

❗ Current head 1ccef51 differs from pull request most recent head 26da404. Consider uploading reports for the commit 26da404 to get more accurate results

@@            Coverage Diff             @@
##               10    #1662      +/-   ##
==========================================
+ Coverage   93.93%   94.16%   +0.23%     
==========================================
  Files         126      126              
  Lines        5737     5643      -94     
==========================================
- Hits         5389     5314      -75     
+ Misses        348      329      -19     

Impacted Files	Coverage Δ
lib/active_graph/node/has_n.rb	98.81% <100.00%> (-0.03%)	⬇️
lib/active_graph/migrations/schema_migration.rb	88.88% <0.00%> (-11.12%)	⬇️
lib/active_graph/migrations/helpers/id_property.rb	86.48% <0.00%> (-1.32%)	⬇️
lib/active_graph/core/cypher_error.rb	88.88% <0.00%> (-1.12%)	⬇️
lib/rails/generators/active_graph_generator.rb	65.45% <0.00%> (-0.62%)	⬇️
lib/active_graph/migration.rb	81.39% <0.00%> (-0.43%)	⬇️
lib/active_graph/node/property.rb	93.93% <0.00%> (-0.35%)	⬇️
lib/active_graph/node/id_property.rb	97.61% <0.00%> (-0.30%)	⬇️
lib/active_graph/config.rb	94.11% <0.00%> (-0.12%)	⬇️
lib/active_graph/node/labels.rb	94.73% <0.00%> (-0.11%)	⬇️
... and 26 more

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