diff --git a/Cargo.toml b/Cargo.toml
index a11575d..d45bdee 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sysfuss"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2021"
 authors = ["NGnius (Graham) <ngniusness@gmail.com>"]
 description = "sysfs wrapper for convenience"
diff --git a/src/basic.rs b/src/basic.rs
index 2174f51..c9998c4 100644
--- a/src/basic.rs
+++ b/src/basic.rs
@@ -20,9 +20,8 @@ impl BasicEntityPath {
     
     pub(crate) fn all(root: impl AsRef<Path>, class: impl AsRef<Path>) -> IoResult<impl Iterator<Item=IoResult<Self>>> {
         let dir_path = root.as_ref().join(SYS_CLASS_PATH).join(class);
-        dir_path.read_dir()
-            .map(
-                |iter| iter.filter_map(
+        Ok(dir_path.read_dir()?
+                .filter_map(
                     |entry| entry.map(
                         |entry| if entry.path().is_file() { None } else { Some(Self::new(entry.path())) }
                     ).transpose()))
@@ -77,6 +76,7 @@ impl crate::SysEntityAttributes<String> for BasicEntityPath {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::SysEntity;
     use crate::SysEntityRawExt;
 
     #[test]
@@ -89,4 +89,45 @@ mod tests {
         }
         Ok(())
     }
+
+    #[test]
+    fn basic_capabilities() -> std::io::Result<()> {
+        let sys = crate::SysPath::default();
+        if std::fs::read_to_string("/sys/class/hwmon/hwmon0/name")?.trim() != "nvme" {
+            // skip if system has different hwmons
+            // TODO account for different test systems
+            eprintln!("basic entity test skipped since hwmon0 is not nvme (maybe running on a different PC?)");
+            return Ok(())
+        }
+        let basic = sys.class("hwmon", crate::capability::attributes([
+            "name".to_string(),
+            "temp1_alarm".to_string(),
+            "temp1_crit".to_string(),
+        ].into_iter()))?.next().expect("Missing any hwmon");
+        let attr_value = crate::SysEntityAttributesExt::attribute::<String, _>(&basic, "name".to_owned()).expect("name capable but also incapable");
+        println!("Attribute ./name = '{}'", attr_value);
+        assert!(attr_value == "nvme");
+        Ok(())
+    }
+
+    #[test]
+    fn basic_drm_capabilities() -> std::io::Result<()> {
+        let sys = crate::SysPath::default();
+        let expected_dev = if let Ok(dev) = std::fs::read_to_string("/sys/class/drm/card1/dev") {
+            dev.trim().to_owned()
+        } else {
+            // skip if system has different hwmons
+            // TODO account for different test systems
+            eprintln!("basic entity test skipped since drm card0 does not exist (maybe running on a different PC?)");
+            return Ok(())
+        };
+        let basic = sys.class("drm", crate::capability::attributes([
+            "dev".to_string(),
+            "uevent".to_string(),
+        ].into_iter()))?.filter(|basic| basic.name().expect("no name").starts_with("card")).next().expect("Missing drm");
+        let attr_value = crate::SysEntityAttributesExt::attribute::<String, _>(&basic, "dev".to_owned()).expect("dev capable but also incapable");
+        println!("Attribute ./dev = '{}'", attr_value);
+        assert!(attr_value == expected_dev);
+        Ok(())
+    }
 }
diff --git a/src/errors.rs b/src/errors.rs
index b641af2..61f9940 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -19,6 +19,26 @@ impl <T1, T2> EitherErr2<T1, T2> {
     }
 }
 
+impl <T> EitherErr2<std::convert::Infallible, T> {
+    /// Convert to non-infallible error
+    pub fn map_infallible_first(self) -> T {
+        match self {
+            Self::First(_e) => panic!("Infallible error cannot exist"),
+            Self::Second(e) => e,
+        }
+    }
+}
+
+impl <T> EitherErr2<T, std::convert::Infallible> {
+    /// Convert to non-infallible error
+    pub fn map_infallible_second(self) -> T {
+        match self {
+            Self::First(e) => e,
+            Self::Second(_e) => panic!("Infallible error cannot exist"),
+        }
+    }
+}
+
 impl <T1: std::fmt::Display, T2: std::fmt::Display> std::fmt::Display for EitherErr2<T1, T2> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
diff --git a/src/hwmon.rs b/src/hwmon.rs
index b3c877e..168d273 100644
--- a/src/hwmon.rs
+++ b/src/hwmon.rs
@@ -4,6 +4,8 @@ use std::io::Result as IoResult;
 
 const HWMON_DIR_PATH: &'static str = "sys/class/hwmon/";
 
+use crate::SysEntityAttributesExt;
+
 /// Attribute representation.
 /// Attribute files are usually in the format `<type><number>_<item>`.
 #[derive(Clone, Copy, PartialEq, Eq)]
@@ -202,7 +204,11 @@ impl HwMonPath {
     pub(crate) fn name(root: &crate::SysPath, name: &str) -> IoResult<Option<Self>> {
         for entry in Self::all(root)? {
             let entry = entry?;
-            if entry.attribute(HwMonAttribute::name())? == name {
+            let value: String = entry.attribute::<String, _>(HwMonAttribute::name()).map_err(|e| match e {
+                crate::EitherErr2::First(e) => e,
+                crate::EitherErr2::Second(_e) => panic!("Infallible"),
+            })?;
+            if value == name {
                 return Ok(Some(entry))
             }
         }
@@ -215,11 +221,6 @@ impl HwMonPath {
         std::fs::read_to_string(self.path.join(name))
     }
     
-    /// Get a hwmon attribute (file contents)
-    fn attribute(&self, attr: HwMonAttribute) -> IoResult<String> {
-        self.attribute_str(&attr.to_attr_str())
-    }
-    
     /// Get the path to a hwmon attribute.
     /// Use `HwMonPath.as_ref().join(attribute_str)` for non-standard attributes
     pub fn path_to(&self, attr: HwMonAttribute) -> PathBuf {
@@ -239,7 +240,7 @@ impl crate::SysEntity for HwMonPath {
     }
     
     fn name(&self) -> IoResult<String> {
-        self.attribute(HwMonAttribute::name())
+        self.attribute(HwMonAttribute::name()).map_err(|e| e.map_infallible_second())
     }
 }
 
@@ -268,10 +269,29 @@ mod tests {
         assert!(!all_hwmon.is_empty());
         for hwmon in all_hwmon.into_iter() {
             let hwmon = hwmon?;
-            assert!(hwmon.attribute(HwMonAttribute::name())? != "");
+            assert!(hwmon.attribute::<String, _>(HwMonAttribute::name()).map_err(|e| e.map_infallible_second())? != "");
+            assert!(!hwmon.attribute::<String, _>(HwMonAttribute::name()).map_err(|e| e.map_infallible_second())?.ends_with("\n"));
             assert!(!hwmon.capabilities().is_empty());
             assert!(hwmon.capabilities().contains(&HwMonAttribute::name()))
         }
         Ok(())
     }
+
+    #[test]
+    fn hwmon_capabilities() -> std::io::Result<()> {
+        let sys = crate::SysPath::default();
+        if !sys.hwmon_by_name("amdgpu").is_ok() {
+            // skip if system has no AMD GPU
+            eprintln!("hwmon test skipped since amdgpu does not exist (maybe running on a laptop PC?)");
+            return Ok(())
+        }
+        let hwmon = sys.hwmon(crate::capability::attributes([
+            HwMonAttribute::name(),
+            HwMonAttribute::new(HwMonAttributeType::Fan, 1, HwMonAttributeItem::Input),
+            HwMonAttribute::new(HwMonAttributeType::Fan, 1, HwMonAttributeItem::Min),
+            HwMonAttribute::new(HwMonAttributeType::Fan, 1, HwMonAttributeItem::Max)
+        ].into_iter()))?.next().expect("Missing capable amdgpu");
+        assert_eq!(hwmon.attribute::<String, _>(HwMonAttribute::name()).expect("name capable but also incapable"), "amdgpu");
+        Ok(())
+    }
 }
diff --git a/src/power_supply.rs b/src/power_supply.rs
index 6e39cb1..3184733 100644
--- a/src/power_supply.rs
+++ b/src/power_supply.rs
@@ -2,8 +2,7 @@ use std::path::{Path, PathBuf};
 use std::convert::AsRef;
 use std::io::Result as IoResult;
 
-use crate::SysEntityRawExt;
-//use crate::SysEntityAttributes;
+use crate::SysEntityAttributesExt;
 
 const PSU_DIR_PATH: &'static str = "sys/class/power_supply/";
 
@@ -218,7 +217,7 @@ impl PowerSupplyPath {
     
     /// Get the power supply type
     pub fn type_str(&self) -> IoResult<String> {
-        self.attribute_str("type")
+        self.attribute(PowerSupplyAttribute::Type).map_err(|e| e.map_infallible_second())
     }
     
     /// Get the power supply type
@@ -267,6 +266,9 @@ impl crate::SysEntityAttributes<PowerSupplyAttribute> for PowerSupplyPath {
             PowerSupplyAttribute::CapacityAlertMin,
             PowerSupplyAttribute::CapacityErrorMargin,
             PowerSupplyAttribute::CapacityLevel,
+            PowerSupplyAttribute::ChargeNow,
+            PowerSupplyAttribute::ChargeFull,
+            PowerSupplyAttribute::ChargeFullDesign,
             PowerSupplyAttribute::ChargeControlLimit,
             PowerSupplyAttribute::ChargeControlLimitMax,
             PowerSupplyAttribute::ChargeControlStartThreshold,
@@ -290,6 +292,8 @@ impl crate::SysEntityAttributes<PowerSupplyAttribute> for PowerSupplyPath {
 mod tests {
     use super::*;
     use crate::SysEntityAttributes;
+    use crate::SysEntityAttributesExt;
+    use crate::SysAttribute;
     
     #[test]
     fn power_supply_all() -> std::io::Result<()> {
@@ -308,4 +312,20 @@ mod tests {
         }
         Ok(())
     }
+
+    #[test]
+    fn power_supply_capabilities() -> std::io::Result<()> {
+        let sys = crate::SysPath::default();
+        if !PowerSupplyAttribute::Type.exists(&sys.power_supply_by_name("BAT0")) {
+            // skip if system has no battery
+            eprintln!("power_supply test skipped since BAT0 does not exist (maybe running on a desktop PC?)");
+            return Ok(())
+        }
+        let psu = sys.power_supply(crate::capability::attributes([
+            PowerSupplyAttribute::Type,
+            PowerSupplyAttribute::Capacity,
+        ].into_iter()))?.next().expect("Missing capable battery");
+        assert!(psu.attribute::<PowerSupplyType, _>(PowerSupplyAttribute::Type).expect("type capable but also incapable") == PowerSupplyType::Battery);
+        Ok(())
+    }
 }