【UT】add ut for spring cloud router plugin

[provenceee]

【修复issue】 #747

【修改内容】add ut for spring cloud router plugin

【用例描述】N/A

【自测情况】run successful with mvn test

【影响范围】N/A

[codecov]

Codecov Report

Merging #758 (b23da46) into develop (c0ea065) will increase coverage by 5.33%.
The diff coverage is 75.00%.

@@              Coverage Diff              @@
##             develop     #758      +/-   ##
=============================================
+ Coverage      26.42%   31.75%   +5.33%     
- Complexity      1574     1931     +357     
=============================================
  Files            617      651      +34     
  Lines          13438    13846     +408     
  Branches        1482     1536      +54     
=============================================
+ Hits            3551     4397     +846     
+ Misses          9440     8887     -553     
- Partials         447      562     +115     

Flag	Coverage Δ
unittests	31.75% <75.00%> (+5.33%)	⬆️

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

Impacted Files	Coverage Δ
...uter/dubbo/declarer/AbstractDirectoryDeclarer.java	0.00% <ø> (ø)
...ubbo/interceptor/AbstractDirectoryInterceptor.java	0.00% <ø> (ø)
...er/dubbo/service/AbstractDirectoryServiceImpl.java	100.00% <ø> (+100.00%)	⬆️
...er/dubbo/service/ApplicationConfigServiceImpl.java	94.44% <ø> (+5.55%)	⬆️
...rmant/router/dubbo/service/ClusterServiceImpl.java	81.81% <ø> (ø)
...ant/router/dubbo/strategy/RuleStrategyHandler.java	100.00% <ø> (+14.28%)	⬆️
...outer/config/label/entity/RouterConfiguration.java	85.71% <ø> (ø)
...spring/interceptor/ServiceRegistryInterceptor.java	83.33% <75.00%> (ø)
...ring/strategy/instance/TargetInstanceStrategy.java	100.00% <0.00%> (ø)
...nt/router/spring/strategy/RuleStrategyHandler.java	100.00% <0.00%> (ø)
... and 83 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[robotLJW]

/lgtm