refactor(context): refactor context handling and improve test robustness (#4066)

Use assert.InDelta for float comparison with tolerance in TestContextGetFloat32
Remove unnecessary blank line in TestContextInitQueryCache
Replace anonymous struct with named contextKey type in TestContextWithFallbackValueFromRequestContext
Update context key handling in TestContextWithFallbackValueFromRequestContext to use contextKey type

Author: kingcanfish

context.go

@@ -951,7 +951,7 @@ func (c *Context) ShouldBindBodyWithTOML(obj any) error {
 	return c.ShouldBindBodyWith(obj, binding.TOML)
 }
 
-// ShouldBindBodyWithJSON is a shortcut for c.ShouldBindBodyWith(obj, binding.JSON).
+// ShouldBindBodyWithPlain is a shortcut for c.ShouldBindBodyWith(obj, binding.Plain).
 func (c *Context) ShouldBindBodyWithPlain(obj any) error {
 	return c.ShouldBindBodyWith(obj, binding.Plain)
 }

context_test.go

@@ -323,7 +323,7 @@ func TestContextGetFloat32(t *testing.T) {
 	key := "float32"
 	value := float32(3.14)
 	c.Set(key, value)
-	assert.Equal(t, value, c.GetFloat32(key))
+	assert.InDelta(t, value, c.GetFloat32(key), 0.01)
 }
 
 func TestContextGetFloat64(t *testing.T) {
@@ -2857,7 +2857,8 @@ func TestContextWithFallbackValueFromRequestContext(t *testing.T) {
 		{
 			name: "c with struct context key",
 			getContextAndKey: func() (*Context, any) {
-				var key struct{}
+				type KeyStruct struct{} // https://staticcheck.dev/docs/checks/#SA1029
+				var key KeyStruct
 				c, _ := CreateTestContext(httptest.NewRecorder())
 				// enable ContextWithFallback feature flag
 				c.engine.ContextWithFallback = true