cleanup(test): use testdata directory in tests (#2202)

The `testdata` directory is both idiomatic and special in Go.

> "The go tool will ignore a directory named "testdata", making
> it available to hold ancillary data needed by the tests."

Ref: https://pkg.go.dev/cmd/go/internal/test

pkg/tools/grype_report_parser_tool_test.go

@@ -6,8 +6,7 @@ import (
 	. "gopkg.in/check.v1"
 )
 
-type VulnerabilityParserSuite struct {
-}
+type VulnerabilityParserSuite struct{}
 
 // Hook up gocheck into the "go test" runner.
 func Test(t *testing.T) { TestingT(t) }
@@ -16,35 +15,36 @@ var _ = Suite(&VulnerabilityParserSuite{})
 
 func (v *VulnerabilityParserSuite) TestNonExistentResult(c *C) {
 	severityLevels := []string{"High", "Critical"}
-	matchingVulnerabilities, err := parseVulerabilitiesReport("mock_data/result_non_existent.json", severityLevels)
+	matchingVulnerabilities, err := parseVulerabilitiesReport("testdata/result_non_existent.json", severityLevels)
 	c.Assert(len(matchingVulnerabilities), Equals, 0)
 	c.Assert(err, NotNil)
 }
 
 func (v *VulnerabilityParserSuite) TestInvalidJson(c *C) {
 	severityLevels := []string{"High", "Critical"}
-	matchingVulnerabilities, err := parseVulerabilitiesReport("mock_data/results_invalid.json", severityLevels)
+	matchingVulnerabilities, err := parseVulerabilitiesReport("testdata/results_invalid.json", severityLevels)
 	c.Assert(len(matchingVulnerabilities), Equals, 0)
 	c.Assert(err, NotNil)
 }
 
 func (v *VulnerabilityParserSuite) TestValidJsonWithZeroVulnerabilities(c *C) {
 	severityLevels := []string{"High", "Critical"}
-	matchingVulnerabilities, err := parseVulerabilitiesReport("mock_data/results_valid_no_matches.json", severityLevels)
+	matchingVulnerabilities, err := parseVulerabilitiesReport("testdata/results_valid_no_matches.json", severityLevels)
 	c.Assert(len(matchingVulnerabilities), Equals, 0)
 	c.Assert(err, IsNil)
 }
 
 func (v *VulnerabilityParserSuite) TestValidJsonForLowVulerabilities(c *C) {
 	severityLevels := []string{"Low", "Medium"}
-	matchingVulnerabilities, err := parseVulerabilitiesReport("mock_data/results_valid.json", severityLevels)
+	matchingVulnerabilities, err := parseVulerabilitiesReport("testdata/results_valid.json", severityLevels)
 	c.Assert(len(matchingVulnerabilities), Equals, 0)
 	c.Assert(err, IsNil)
 }
+
 func (v *VulnerabilityParserSuite) TestValidJsonForMatchingVulerabilities(c *C) {
 	severityLevels := []string{"High", "Critical"}
 	expectedIds := []string{"CVE-2016-10228", "CVE-2016-10229"}
-	matchingVulnerabilities, err := parseVulerabilitiesReport("mock_data/results_valid.json", severityLevels)
+	matchingVulnerabilities, err := parseVulerabilitiesReport("testdata/results_valid.json", severityLevels)
 	c.Assert(len(matchingVulnerabilities), Equals, 2)
 	c.Assert(err, IsNil)
 	for index, vulnerability := range matchingVulnerabilities {