Test enhancement

[peter279k]

Changed log

• The php-7.1.33 version is latest stable php-7.1 version now.
• Remove trusty dist and these php-7.x versions are enabled on xenial dist by default.
• Upgrade the PHPUnit version to be ^7.0||^8.0. To be compatible with PHPUnit 7.x and PHPUnit 8.x versions, it should add :void to be compatible with PHPUnit\Framework\TestCase::setUp method.
• Using the assertTrue and assertFalse assertions to assert expected value is true or false.

[coveralls]

Pull Request Test Coverage Report for Build 165

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 86.735%

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Totals
Change from base Build 163:	0.0%
Covered Lines:	85
Relevant Lines:	98

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 165

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 86.735%

---

Totals
Change from base Build 163:	0.0%
Covered Lines:	85
Relevant Lines:	98

---

💛 - Coveralls

[DivineOmega]

Thank you!