Add more tests (#4)

This also refactors some of the code parsing logic.

Reviewed-on: #4
Co-authored-by: Anna Rose Wiggins <annabunches@gmail.com>
Co-committed-by: Anna Rose Wiggins <annabunches@gmail.com>

internal/mappingrules/mapping_rule_base_test.go

@@ -0,0 +1,53 @@
+package mappingrules
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type MappingRuleBaseTests struct {
+	suite.Suite
+}
+
+func TestRunnerMappingRuleBaseTests(t *testing.T) {
+	suite.Run(t, new(MappingRuleBaseTests))
+}
+
+func (t *MappingRuleBaseTests) TestNewMappingRuleBase() {
+	t.Run("No Modes", func() {
+		base := NewMappingRuleBase("foo", []string{})
+		t.Equal("foo", base.Name)
+		t.EqualValues([]string{"*"}, base.Modes)
+	})
+
+	t.Run("Has Modes", func() {
+		base := NewMappingRuleBase("foo", []string{"bar", "baz"})
+		t.Equal("foo", base.Name)
+		t.Contains(base.Modes, "bar")
+		t.Contains(base.Modes, "baz")
+		t.NotContains(base.Modes, "*")
+	})
+}
+
+func (t *MappingRuleBaseTests) TestModeCheck() {
+	t.Run("* works on all modes", func() {
+		base := NewMappingRuleBase("", []string{})
+		mode := "bar"
+		t.True(base.modeCheck(&mode))
+		mode = "baz"
+		t.True(base.modeCheck(&mode))
+	})
+
+	t.Run("single mode only works in that mode", func() {
+		base := NewMappingRuleBase("", []string{"bar"})
+		mode := "bar"
+		t.True(base.modeCheck(&mode))
+		mode = "baz"
+		t.False(base.modeCheck(&mode))
+	})
+
+	t.Run("multiple modes work in each mode", func() {
+
+	})
+}